remove origin validation

ALLOW_ANY_ORIGIN, ALLOW_ANY_ORIGIN_MUSIC, and everything they gated. The flag
defaulted to ON, so none of it ran on a real install — what comes out is
documented defence in depth that was already switched off. The file said so
itself: "Both flags and their call sites come out once the tailnet is the
perimeter."

Origin was never authentication here in any case. An app's `officer://<hex>`
origin is chosen by the client, forgeable outside a browser, and extractable from
a shipped binary.

Gone: the two flags, isOriginAllowed, isOriginCheckDisabled, isMusicOriginExempt,
originValidationMiddleware, ORIGIN_RULES and the whole OFFICER_<APP>_ORIGIN
scheme, PUBLIC_URL's origin/host derivation, and origin-validation.test.ts, which
existed only to pin them. CORS now echoes whatever Origin it is given, which is
what every install already did.

What SURVIVES is the reason this needed care. origin-validation.ts held two
unrelated things, and the second was the global authorization gate — a valid
non-owner token reaches only what its role grants, deliberately NOT under the
flag because it is account-based rather than origin-based. Its own comment called
it "the airtight half". Deleting the file wholesale would have deleted
authorization.

So it moves to _middlewares/capability-gate.ts as capabilityGateMiddleware, with
the name matching what it does: nothing in it reads an Origin header any more.
hono.ts mounts it in the same position, ahead of every router.

origin-middleware.ts stays and is untouched — it extracts the Origin for six auth
handlers that log it, and for passkeys. Extraction, not validation.

Also updates every claim that rested on the old model: CLAUDE.md's security
section and repo map, docs/secret-store.md, docs/mobile-api-keys.md, and five
messages in machine-setup's Tailscale section which told the owner to set
ALLOW_ANY_ORIGIN=false when declining a tailnet. That advice is now impossible to
follow, and the honest version is different: with no tailnet the token is the
whole lock, so put a proxy in front and restrict who can reach it.

Not typechecked (empty node_modules, frozen installs). Every changed file parses;
the setup section was run and writes four variables now.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

src/servers/api/users/capabilities-routes.ts

@@ -13,7 +13,7 @@ import { capabilityAvailability } from '../../app-store/availability';
 // `/user/capabilities` answers "what may I do" for the caller, and every account may ask. The dock, the
 // app registry and the route guards all read it, so it is the frontend's whole view of the permission
 // model — and it must never be the frontend's ENFORCEMENT of it. Hiding a dock icon is a courtesy; the
-// 403 in origin-validation is the lock.
+// 403 from the capability gate is the lock.
 //
 // Everything else here is owner-only and edits the policy itself.
 

src/servers/api/users/users-router.ts

@@ -15,8 +15,8 @@ usersRouter.use(originMiddleware);
 // Self-update. Any signed-in account may change its own name, username and avatar.
 usersRouter.put('/', updateUserHandler);
 
-// Everything below manages OTHER accounts and is the owner's alone. The global capability backstop in
-// originScopeMiddleware already refuses a non-owner here — `user-admin` is `kind: 'admin'`, so it is
+// Everything below manages OTHER accounts and is the owner's alone. The global capability gate in
+// hono.ts already refuses a non-owner here — `user-admin` is `kind: 'admin'`, so it is
 // not grantable — but that router-level rule cannot see the one exception beside it: `PUT /` is
 // declared `selfService` so every account can edit its own profile. This gate is what keeps that
 // exception from widening to the routes below it, and it is a second lock rather than a restatement.