# CLAUDE.md

## Project Overview

Officer is a self-hosted platform built around one person — the server owner — which since 2026-08-07
also admits **additional accounts holding a strict subset of it**. It bundles an AI agent, a terminal,
a file browser, a code editor, email, a bitcoin wallet, a remote desktop and customisable dashboards
behind a single web app.

**The owner/member split, and where the line falls.** This file said "single-user is a hard invariant,
not a stage" until 2026-08-07. That is no longer true and had already stopped being true when it was
written: `users` holds six rows. The accurate statement is narrower and more useful —

- **One owner.** User id 1, role `Super Admin`, created by `POST /auth/bootstrap` while the table is
  empty, pinned there by a CHECK constraint. The owner bypasses every permission check.
- **Other accounts get only what their ROLE is granted.** Roles are `Admin`, `Member`, `Developer`;
  grants live in `role_capabilities`, keyed on role, never on user. Absence denies — there is no row
  meaning "no", so an empty table is a server where members reach nothing but their own profile.
- **Some things can never be shared, structurally.** Tasks, items, desktop and browser are
  `kind: 'execution'`: they run as the owner's OS user in the owner's home, so there is no level of
  "read" that makes them safe. They have no level at all and the grants API refuses to store one.
- **And some are shared only because the kernel enforces it.** Terminal, chat and files are
  `kind: 'confined'`, added 2026-08-11 with per-user Linux accounts. They still touch the filesystem
  and still run processes — but not the *owner's*, because the account has its own Linux user, its own
  home, and the kernel refusing everything above it.

  The distinction earns its keep in one place: **a confined grant means nothing without that Linux
  user.** `authorize.ts` drops it for an account whose `osUser` is null, so "granted but unconfined"
  resolves to no access rather than to the owner's home — which is what it would otherwise resolve to,
  since `getOwnerHomeDir` ignores the email it is passed. That rule lives there once and covers the
  HTTP routes, the websocket doors and the dock together.

So "which user is this" has a real answer for the **app** surface (gitea, music, photos, email,
calendar…) and for the **confined** one (terminal, chat, files), and is still always "the owner" for
anything under `execution`.

`src/servers/capabilities/registry.ts` is the authority and reads as the design document for this.
**Mounting a router without a registry entry makes the server refuse to boot** — see "Capabilities"
below before adding one.

**Still single-user: account creation.** `createUser` has exactly one call site, `auth/bootstrap.ts`,
gated on an empty table. There is no signup route, no invite flow and no admin create-user handler, so
every existing member was inserted into Postgres by hand. That is the largest gap in the model, not a
deliberate boundary.

## Architecture

One Bun process (`src/server.tsx`) serves everything:

- the React SPA, via Bun's HTML import of `src/apps/officer-web/index.html` (HMR in dev)
- the REST API, a Hono app mounted at `/api` (`src/servers/hono.ts`)
- eight WebSocket providers — terminal, chat, task-runner, pipeline, cliamp, cliamp-audio, desktop,
  vault — plus a sidecar registration socket. `terminal` is a byte relay onto the pty sidecar's own
  listener, not a translating bridge; `vault` is the same shape onto Vaultwarden's notifications hub.
- ~~a browser relay on its own port~~ — switched off 2026-08-13, awaiting extraction into a plugin.
  The extension and `api/browser/` stay on disk; the listener and the `/api/browser` mount do not.

Long-running and privileged work lives in **sidecars**: separate processes that dial back in over
`/api/sidecar/register` and are tracked in `src/servers/sidecar-registry.ts`. PM2 runs them
(the generated `ecosystem.config.cjs` — see below): `officer` (the server), `officer-anthropic-proxy`, `officer-claude-code`,
`officer-opencode`, `officer-email`, `officer-pty`, `officer-vnc`, `officer-music`, `officer-vault`,
`officer-slskd`, `officer-headscale`, `officer-transmission`, `officer-invoiceshelf`, `officer-wallet`,
`officer-photos`, `officer-notify`, `officer-caldav`, `officer-memos`, `officer-jellyfin`, `officer-gitea`
— twenty as of 2026-08-06, and a list that goes stale every time a sidecar lands. `pm2 jlist` is the
source of truth.

**`officer-anthropic-proxy` and `officer-claude-code` are not the same thing.** (The second was
called `officer-agent` until 2026-08-13; older docs use that name.) The proxy holds the Anthropic
credential and forwards API traffic; the agent is the process that spawns `claude`. They were one entry
named `officer-claude` until the sidecar-isolation work — which is exactly how the false claim that
"restarting officer doesn't disturb the agent" survived so long. Every sidecar is a PM2 peer of
`officer`, so **no sidecar is a child of the server and restarting the server does not kill one.**

Agents run **unsandboxed as the server owner**, with `--dangerously-skip-permissions`. This is
deliberate — it is the owner's own machine. Do not add a jail without being asked.

## Repository Layout

```
src/
├── server.tsx              # the single entrypoint: routes, WS upgrades, static files
├── apps/
│   ├── officer-web/        # the SPA shell — Screens/Authentication + Screens/Dashboard
│   └── landing/            # marketing landing page
├── servers/
│   ├── hono.ts             # router composition; everything under /api
│   ├── _middlewares/       # auth, body parsing, the capability gate, rate limiting
│   ├── api/<feature>/      # one folder per feature, each exporting a router
│   ├── channels/           # send-claude-code / send-opencode — how /chat drives an agent turn
│   ├── queue/              # background job engine
│   └── sidecar/            # sidecar implementations + the wire protocol
├── databases/officer_db/   # the only database (Postgres + Drizzle)
├── extensions/browser-relay/
└── workspaces/             # shared packages, each a bun workspace
```

`src/workspaces/officerdev` is the biggest of these: the windowed "apps" (FileBrowser, Chat,
Terminal, CodeEditor, Desktop, Dashboards, Wallet…) that the shell hosts, behind an `AppRegistry`.
`src/apps/officer-web` is only the shell — screens, routing and settings.

**Path aliases** (`tsconfig.json`): `@/*` → `src/apps/officer-web`, `@/components/*` →
`src/workspaces/components`, `@@/*` → `src/servers`, `@/public/*` → `public`. Workspace packages are
imported by their package name (`officerdev`, `hooks`, `state`, `types`, `helpers`, …).

## Tech Stack

- **Runtime**: Bun (Node 22 or newer is enforced by a `preinstall` check)

  That check demanded *exactly* 22 until 2026-08-12. The reason was a `node-pty` build
  failure some months earlier, whose details were not recorded. It was relaxed to `>= 22`
  after confirming node-pty ships **no Linux prebuilds** — its install script always falls
  through to `node-gyp rebuild`, so it compiles against whatever Node is present and there
  is no ABI to mismatch. Untested on 24 at the time of the change. If `bun install` fails
  building node-pty, or `officer-pty` cannot load its native module, restore the exact pin
  first. The source build also needs `build-essential` and `python3`.
- **Language**: TypeScript, strict. `bunx tsgo` is clean — keep it that way.
- **Frontend**: React 19, React Router 7, React Query, Tailwind 4, shadcn/ui + custom components
- **Backend**: Hono
- **Database**: one Postgres database via Drizzle
- **Agents**: Claude Code and opencode, driven through sidecars; tools exposed over MCP

## Data

Two stores, and the split matters:

**Postgres** (`src/databases/officer_db`) holds the account, passkeys, settings, dashboards,
email accounts, queue and pipeline jobs. One directory per feature holding `schema.ts` and
`queries.ts` beside each other; `src/schema.ts` is what `db:push` reads, and it lists the core tables
with the plugin ones commented out. Types inferred from the schema in `src/types.ts`.

**The filesystem** holds everything the agent authors. `OFFICER_ITEMS_DIR` (`$OFFICER_ROOT/capabilities`)
contains one directory per item under `skills/`, `tools/`, `tasks/`, `processes/`, `extensions/` — no
database rows, no scope tiers. `DATA_PATH/<email>/` holds the managed home, attachments and the
per-account email SQLite stores — those are the **email sidecar's**, and nothing in the platform opens
them.

**None of those paths is configured.** Since 2026-08-13 `src/servers/data-path.ts` derives the install
root as `resolve(process.cwd(), '..')` and hangs `data/`, `capabilities/` and `dockers/` off it. That
replaced `DATA_PATH`, `OFFICER_ITEMS_DIR` and `HOME_DIR` in `.env` — three values that had to agree with
each other and with the tree on disk. `assertInstallLayout` refuses to boot when the working directory
is not the repo, because otherwise a wrong `cwd` relocates the whole install silently rather than
failing.

Note `getHomeDir` (the managed home under `DATA_PATH`, now used only for NON-owner accounts and by
pipeline-executor) versus `getOwnerHomeDir` (the owner's real login home, where terminals, chats and
task runs execute — captured from `homedir()` once at module load, and it ignores the email it is
passed).

### Schema changes use `push`, not migrations

This database is kept in sync with `bun db:push`, which diffs the schema code against the live
database and alters it directly. **`drizzle-kit migrate` has never been run here** — there is no
`__drizzle_migrations` table. Change the schema, run `bun db:push`, done.

`bun db:gen` writes files to `officer_db/migrations/`, but nothing applies them; the old numbered
history was deleted because it had drifted from the real schema. Treat the schema code, not those
files, as the source of truth.

**Declare multi-column uniqueness as `uniqueIndex('uq_…').on(a, b)`, never `unique('uq_…').on(a, b)`** —
drizzle-kit mis-diffs named composite unique _constraints_ and re-creates them on every push, which used
to stop `db:push` on an unanswerable truncate prompt. Same for any foreign key whose generated name would
exceed Postgres's 63-character identifier limit: name it explicitly. See `src/databases/CLAUDE.md` →
"Composite keys" before adding either.

## Security Model

- `IS_DEV_BUILD` (`src/servers/build-env.ts`) is true **only** when `PUBLIC_BUILD_ENV` is explicitly
  `dev`/`development`. Everything else, including unset, is hardened. Rate limiting and password
  rules key off it — they fail closed.
- **There is no origin checking.** It was removed on 2026-08-13, along with `ALLOW_ANY_ORIGIN` and
  `ALLOW_ANY_ORIGIN_MUSIC`. The flag defaulted to ON, so origin validation ran on no real install —
  what came out was documented defence in depth that was already switched off. Origin was never
  authentication here anyway: an app's `officer://<hex>` origin is chosen by the client, forgeable
  outside a browser, and extractable from a shipped binary. The perimeter is the tailnet, and the lock
  is a valid token on every protected route plus the capability gate below.
- JWTs are 30-day, blacklisted on signout, and invalidated by a password change (`passwordChangedAt`).
  **The role is deliberately not a claim** — every authorization decision re-reads `users.role` from
  Postgres, so a grant or a revoke takes effect on the next request rather than at next sign-in.
- A panic lockdown (`src/servers/api/auth/panic.ts`) is in-memory only and refuses every
  authenticated request until the server restarts.

### Capabilities — read this before mounting a router

Authorization is one system, and it is not in `userMiddleware` (which only answers "is this token
valid"). It is `_middlewares/capability-gate.ts` → `capabilities/authorize.ts`, mounted globally in `hono.ts`
ahead of everything, and it re-verifies the token itself so it covers routes that never mount
`userMiddleware`.

- `capabilities/registry.ts` — the single enumeration of what the platform can do, in five kinds:
  `core` (every account, not deniable), `app` (**the grantable surface**), `confined` (grantable, but
  only to an account that has a Linux user), `execution` and `admin` (owner only, and `execution` is
  never grantable at any level). 27 entries as of 2026-08-13.
- `capabilities/authorize.ts` — resolves "may this account do this". Owner short-circuits first; every
  other answer is role grants plus core, with `execution`/`admin` stripped even if a row grants them,
  and `confined` stripped for an account with no `osUser`.
  **Every catch returns deny.** Grants are cached by role and the cache's whole invalidation contract
  is `invalidateRoleGrants`, called by the one writer in `api/users/capabilities-routes.ts`.
- `capabilities/totality.ts` — `assertCapabilityTotality` runs in `server.tsx` **before `serve()` and
  throws**. Mount a router or a socket without a registry entry and `pm2 restart officer` fails,
  naming what is missing. That is deliberate: the hole it closes was a Member 403'ing on
  `GET /api/tasks` and opening `/api/tasks/pipeline/ws` with a 101 in the same minute, because Bun's
  route table matches the socket before the `/api/*` catch-all that reaches Hono. A patch does not
  survive the next door; refusing to boot does.

So **adding a router means adding one line to `CAPABILITIES`**. If the surface genuinely is not
user-gated, add it to `EXEMPT_API_PREFIXES` in `totality.ts` _with a reason_ — an unexplained exemption
is how the hole happened the first time.

The frontend hook `useCapabilities` **fails open** on purpose: hiding a dock icon is a courtesy, the
403 is the lock, and an owner locked out by a transient network error is worse than a member clicking
into a refusal.

## Commands

```bash
bun dev          # the whole app — SPA + API + WebSockets, watched
bun start        # production
bunx tsgo        # typecheck (not tsc)
bun test         # tests
bun format       # prettier over every dirty file — see the note below before running it
bun db:push      # apply the schema to Postgres
bun setup        # runs scripts/install.sh — blank machine to running platform
```

`scripts/install.sh` is only an orchestrator — it runs the two halves in order and does nothing itself:
`setup/machine-setup/machine-setup.sh` (28 sections: packages, tailnet, runtimes, docker, shell) then
`setup/officer-setup.sh` (11: pre-flight, layout, repository, dependencies, database, environment, secrets,
schema, build, services, verify). Either runs alone — `--machine-only`, `--officer-only`, or by path — because
a machine you already trust needs only the second. Both are re-runnable: each records the steps it finished
and skips them, so stopping halfway costs nothing. **Run it as yourself**; it re-execs through `sudo` when it
needs to, and on macOS never does, because Homebrew refuses to run as root.

Sidecar control is PM2, not npm scripts: `pm2 restart officer-<name>`, `pm2 logs officer-<name>`.
See `docs/working-on-officer.md` for which process a given change needs restarted.

### Installs are frozen. Never resolve a dependency you did not ask for.

`bunfig.toml` sets `[install] frozenLockfile = true`, so **`bun install` resolves from `bun.lock` and
nothing else** — it fails rather than quietly picking up a newer version, including a transitive one
nobody chose. Verified on bun 1.3.10: a lockfile that no longer satisfies `package.json` exits 1 with
`error: lockfile had changes, but lockfile is frozen`.

It is config rather than a habit because a supply-chain compromise does not wait for the one time
somebody forgets a flag. On **2026-08-04** eleven cache packages — `keyv`, `flat-cache`,
`file-entry-cache`, `cacheable-request`, `cache-manager`, the `@cacheable/*` scope, `ecto` — were
published with a `preinstall` dropper that harvested npm and GitHub tokens, AWS and Kubernetes
credentials, SSH and PEM keys, `.env` files and `.claude/settings.json`, then republished itself
through any npm token it found. It reached 434 further packages across 1,381 versions. This machine was
unaffected only because nothing had installed since 2026-08-02.

**To change a dependency:** edit `package.json`, run `bun install --no-frozen-lockfile` deliberately,
**read the lockfile diff**, and commit it. The friction is the point — an unexplained lockfile change
in a diff is the signal this exists to produce.

**Do not** add `--no-frozen-lockfile` to a script, a Dockerfile or CI to make an error go away. The
error means the lockfile and `package.json` disagree, and that is worth a human look every time.

**Format your own files, not the whole dirty tree.** `bun format` globs `git diff --name-only HEAD`,
so it rewrites every uncommitted file — including work in progress that isn't yours, which then shows
up as unexplained whitespace churn in someone else's diff. Run `bunx prettier --write <paths>` on the
files you actually touched. `bun format` is only safe when the tree is otherwise clean.

## Code Style

- **Paradigm**: functional — pure functions, immutability, composition
- **TypeScript**: strict, no `any`. Type-only imports are required (`verbatimModuleSyntax`).
- **Comments**: minimal, and about _why_. Don't narrate what the code already says.
- **Async**: always async/await
- **Exports**: named only, no defaults
- **Files**: `PascalCase.tsx` for components, `kebab-case.ts` for everything else
- **Prettier**: single quotes in JS, double in JSX, semicolons, trailing commas, 120 cols

### Imports

Order: types → external → workspace → relative.

```ts
import type { User } from 'types';
import { useState } from 'react';
import { useQuery } from '@tanstack/react-query';
import { useClient } from 'hooks/useClient';
import { formatDate } from 'helpers/formatters';
import { useWebsites } from '../useWebsites';
```

In app code import types from `'types'`, which re-exports the database types. Only server and
database code imports from `officerdb/types` directly.

### Functions

Arrow functions for one-liners, regular functions for anything with real logic. No multiline
parameter lists — extract a params type instead.

```ts
type ProcessDataParams = { body: Record<string, unknown> | undefined; query: Record<string, string> };
export function processData({ body, query }: ProcessDataParams): Result { ... }
```

### Components and hooks

```tsx
type ExperimentCardProps = { experiment: Experiment; onSelect: (id: number) => void };

export const ExperimentCard = ({ experiment, onSelect }: ExperimentCardProps) => { ... };
```

Complex hooks return objects; simple state hooks return `as const` tuples. Event parameters are
always named `ev`, never `e`.

### API calls

`useClient()` returns typed verbs — `client.get<Foo>('/foo')` really does return `Foo`, so pass the
type parameter and let inference flow from it.

## Working With Me

- **Ask first** — confirm the approach before a significant change
- **Explore thoroughly** — read the related files before editing
- **Keep it simple** — no over-engineering, no premature abstraction
- **Be explicit** — no magic, no implicit behaviour
- **Stay focused** — note unrelated problems, don't fix them uninvited
- **Report honestly** — say what you verified and what you didn't

**Always commit and push when you finish implementing — including when it went wrong.** Don't wait to be
asked, and don't hold a branch back because it is unfinished, untested or turned out to be a dead end. The
history of the mistakes is worth having: a reverted commit and its message explain why an approach was
abandoned, which is exactly the thing that gets lost when a failed attempt is quietly discarded. Say what
state it is in — in the commit message and in `COMMS/` if another agent will pick it up — rather than
withholding the commit until it is good.

Commit messages: simple lowercase, no prefixes.

## Frontend route conventions (apply to EVERY new dashboard route)

Worked examples: `/soulseek`, `/music`, `/chat`.

- **Workspace/Panel framework, always — never a standalone single screen.** The screen renders
  `<WorkspaceView workspace={ws} locked />` where
  `ws = useDashboardState<LayoutNode>('screens/<name>', defaultLayout)`, guarded by a `normalizeLayout`
  that pins `appType`s to an allow-list. Panels are windowed apps under
  `src/workspaces/officerdev/src/apps/<Feature>/`, each exporting `appRegistryMetas`
  (`{ key, name, icon, component, availableOnPanel: false }`) and registered in `AppRegistry.tsx`.
  The Workspace/Panel framework is orthogonal to routing — it contains no route navigation, and panels
  live inside the Route element tree, so they can call `useParams`/`useSearchParams` directly.
- **Page title by route.** Add a rule to `RULES` in `src/apps/officer-web/state/usePageTitle.ts`
  (`{ match: (p) => p.startsWith('/<name>'), title: '<Name>' }`, most-specific first);
  `usePageTitleSync` does the rest. `startsWith` means nested routes are covered.

### The URL is the source of truth for selection

`docs/navigation-audit.md` is the authority here — read it before building a screen that selects
things. It names the **"opaque click" anti-pattern**: an element that opens something addressable but
keeps the id in an onClick closure instead of the DOM, leaves the URL unchanged, holds the selection
in `usePanelChannel`/`useGlobal`, and has no anchor semantics (no cmd-click, no middle-click, not
link-focusable). Half the app still does this; none of the new code should.

- **Addressable state goes in the URL** (`useParams` / `useSearchParams`), never in a channel.
  `usePanelChannel` is for genuine signals and refresh buses (`files:refresh-signal`,
  `SLSKD_REFRESH_CHANNEL`, `MUSIC_RESYNC_CHANNEL`) — and declare one with `defineChannel` in
  `officerdev/src/channels.ts` rather than spelling the name and type at each site.
  "Which thing is open" is a URL. Panels each read the URL rather than passing it between themselves.
- **Rows and nav items are real links.** `<Link>` for rows (exemplar: the `/chat` session list,
  `f35c145`); **react-router's `<NavLink>`** for nav chrome, so active state comes from the router.
  The hand-rolled `isActive` in `Dock`/`Header` is scheduled for replacement (audit Phase 4) — don't
  copy it. A disabled entry renders as a `<span>`; a disabled `<a>` is not a thing. A control that
  _mutates_ rather than navigates stays a `<button>`.
- **Route pairs.** A bare screen route plus a param route rendering the same component: `/chat` +
  `/chat/:sessionId`, `/jobs` + `/jobs/:id`, `/email` + `/email/:emailId`, `/headscale` +
  `/headscale/:section`. One `<Navigate … replace />` guard in the screen, placed after all hooks,
  canonicalises both the bare route and a bogus param.
- **Master list + live preview uses `?selected=<id>`**, not the detail route — linking rows straight
  to `/x/:id` destroys preview-on-list, because that route is the full page. Rows link to
  `/x?selected=id` on-page and `/x/:id` off-page; list, mobile panel and preview all read the param.
  Action buttons are **siblings** of the anchor, never nested inside it.
- **`src/workspaces/components/NavLink.tsx` is not react-router's `NavLink`** — it's a `<Link>`
  wrapper that appends `useGlobalQueryString()` and provides no active state. Import react-router's
  when you want `isActive`.
- Route helpers shared between an `officerdev` panel app and an `officer-web` screen must be
  re-exported from `src/workspaces/officerdev/src/index.ts` (named exports only — the barrel
  deliberately avoids `export *` for app modules to keep `appRegistryMetas` from colliding).

## COMMS — a channel between agents, when one is open

`COMMS/<work-stream>/` is a **tracked** channel between agents working on this repo from different machines.
It exists because findings used to reach each other by the owner relaying them from memory at the end of long
sessions.

**There is no open channel right now.** `COMMS/sidecar-app-store/` ran for one night — per-user Linux
accounts through to a member's first agent turn — and was deleted when the work landed, which is the
convention rather than an oversight: a spent channel left in place gets read as current.

If you open one:

- **Read it before starting**, if your task touches its work stream. It carries what is verified, what is
  assumed, what is broken, and what is waiting on a decision — the parts a commit message does not hold.
- **Number the files and alternate**, one per turn, odd for one agent and even for the other. The parity is
  the author; the alternation is the protocol. A push with no doc is then visibly a break rather than
  something to find by diffing, and "nothing to report" is still a turn worth taking — silence and a crashed
  agent read identically.
- **End on a checkable condition**, not on either party's judgement: no open item is actionable by a
  participant. "I think we're done" can close a thread with work still in it.
- **Durable reasoning goes in `docs/` or next to the code.** The channel is for coordination. When the work
  lands, delete the channel and move anything still open to `TODO.md`.

Two things that made it work, and neither is about either agent being more careful. One writes, the other
verifies, and only the verifier runs things on a real machine — most of what was caught was invisible to
reading and needed a live filesystem. And the author of a comment is the worst-placed person to notice the
code disagrees with it: the two most serious defects were both found by whoever had not written the sentence
explaining why it was safe.

## Further Reading

- `docs/navigation-audit.md` — **authoritative** on routing/navigation: the opaque-click anti-pattern,
  a severity-ranked findings table, the channel-selection map and the four-phase plan
- `docs/agent-coordination.md` — **the north star** for the workspace/panel work: agents on one
  dashboard coordinating with each other instead of through the human, the handoff protocol, and what
  is deliberately _not_ being built. Read it before ranking, deferring or starting any panel item —
  it is what `docs/workspace-panel-todo.md` is ranked against.
- `docs/workspace-panels.md` — how the Workspace/Panel framework works: the layout tree, how a panel is
  mounted and what it knows, the URL-vs-channel split for panel-to-panel communication, and the
  persistence key families. Read before building a panel app. Its defect list is
  `docs/workspace-panel-todo.md`.
- `docs/secret-store.md` — **design, not built**: moving the encryption and signing keys out of `.env`
  into a SQLite store, why they cannot live in Postgres, and key rotation. Also records the core/plugin
  split it assumes — light plus `officer-headscale` is the core; Vaultwarden and the wallet are plugins
- `docs/sidecar-topology.md` — where the sidecar architecture is going, and what was considered and dropped
- `docs/working-on-officer.md` — how to run, restart and check your work on this machine
- `docs/wallet-key-custody.md` — what the platform can and cannot see of the wallet
- `TODO.md` — current direction and deferred work; **takes precedence over this file where they disagree**
- `src/apps/CLAUDE.md` — shared frontend patterns
- `src/databases/CLAUDE.md` — database patterns
- `CONVENTIONS.md` — component organisation, state management and React patterns, with rationale;
  `src/workspaces/officerdev/APP_CONVENTIONS.md` and `HOOK_CONVENTIONS.md` for panel apps and hooks

Treat the code as the source of truth where anything here disagrees with it.
