finish the offscale sweep: two real remnants and eleven stale names

Asked for a thorough check that nothing of offscale is left in the platform. The
extraction was sound — no router, no permission entry, no app-store entry, no
screen, no panel app, no env var anything reads. Two things were genuinely wrong,
and both were in setup rather than in the server.

── The secret store minted a key for a plugin ──

`officer-setup` bootstrapped two purposes: `jwt` and `headscale`. The second was a
key for a PLUGIN, under a name the rename had already replaced, on a machine where
the plugin is not installed and nothing would ever ask for it. offscale encrypts
under `offscale`, and `getKey` creates on demand — which is precisely what lets
core know nothing about plugins. Now core bootstraps `jwt` alone.

── `.env.example` documented variables for a deleted router ──

HEADSCALE_URL, HEADSCALE_API_KEY and HEADSCALE_USER were described as driving
`/api/vpn`. That router was deleted on 2026-08-14 and nothing has read any of them
since. Left as a note saying where the tailnet's credentials live now, because
somebody with an older `.env` will otherwise wonder why setting them does nothing.

── Names that outlived the thing ──

Eleven comments referred to the plugin's route, panels, console or server registry
as "headscale": three sidecar config files describing their own shape by pointing
at it, two screens citing `/headscale` as the example of a Workspace/Panel route,
the terminal's note about the Console, and the photos types. Also `catalogue.ts`,
which still claimed headscale "is CORE now", and `working-on-officer.md`, which
told the reader a core install runs six processes including `officer-headscale`.

Upstream references are deliberately untouched: "Headscale's API", "the Headscale
admin credential", "is this a Headscale server?" all name the thing the plugin
drives, and renaming those would make the sentences false.

`docs/secret-store.md` argued headscale must be core because the tailnet is the
perimeter. Marked superseded rather than deleted, with the distinction that
settles it: the perimeter is the tailnet EXISTING, which machine-setup still
arranges on a core install — not the platform shipping the screen that
administers it.

Verified by counting: live code, setup provisioning, env references, permission
entries, app-store entries, hono mounts, dock defaults, screens and panel apps all
zero. What is left is generated files (Plugins.gen, plugin-schemas.gen), the
bundled catalogue entry, test fixtures using "offscale" as an example app name,
and history.

tsgo clean, frontend builds, 873 pass / 7 fail unchanged, setup scripts parse.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/apps/officer-web/Screens/Dashboard/Invoices/InvoicesScreen.tsx

@@ -4,7 +4,7 @@ import { DEFAULT_INVOICES_SECTION, invoicesSectionPath, isInvoicesSection, Works
 import { useDashboardState } from 'state/useDashboardState';
 import { defaultLayout } from './defaultLayout';
 
-// /invoices uses the Workspace/Panel system (like /transmission and /headscale): the section nav on the
+// /invoices uses the Workspace/Panel system (like /transmission and /offscale): the section nav on the
 // left, the section itself on the right. Both panels talk to the officer-invoiceshelf sidecar through the
 // /api/invoiceshelf auth proxy — the InvoiceShelf URL, its Sanctum token and the company header live in the
 // sidecar and never reach the browser.

src/apps/officer-web/Screens/Dashboard/Transmission/TransmissionScreen.tsx

@@ -9,7 +9,7 @@ import {
 import { useDashboardState } from 'state/useDashboardState';
 import { defaultLayout } from './defaultLayout';
 
-// /transmission uses the Workspace/Panel system (like /headscale): a filter nav on the left and the section
+// /transmission uses the Workspace/Panel system (like /offscale): a filter nav on the left and the section
 // view on the right. Both talk to the officer-transmission sidecar through the /api/transmission auth proxy,
 // which holds no Transmission credentials of its own — the RPC URL and any Basic auth live in the sidecar.
 //