minesweeper: narrow send(), and tell the ws mirror about the provider

two failures another session found in a shared checkout, both mine.

send() took a plain Uint8Array, whose default buffer type is
ArrayBufferLike and may be a SharedArrayBuffer — WebSocket.send takes
only BufferSource. narrowed to Uint8Array<ArrayBuffer>, which every
caller already builds and which the terminal relay already does.

registry.test.ts keeps REAL_WS as a hand-written mirror of server.tsx's
handlers map, and its own comment says that drift is what it catches. it
caught mine: the route and the registry entry landed, the mirror did not.

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

src/servers/permissions/registry.test.ts

@@ -23,7 +23,7 @@ import { assertPermissionTotality, isExemptApiPath } from './totality';
 // switched off 2026-08-13. It was listed here until 2026-08-18 and made this file's own totality tests
 // fail for five days — the mirror claiming a provider the server does not serve, which is precisely the
 // drift the comment above warns about, caught by the check and then ignored because it was "the baseline".
-const REAL_WS = ['terminal', 'chat', 'chat-notify', 'task-runner', 'pipeline', 'sidecar'];
+const REAL_WS = ['terminal', 'chat', 'chat-notify', 'task-runner', 'pipeline', 'sidecar', 'minesweeper'];
 const realApi = () => [...new Set(PERMISSIONS.flatMap((c) => c.api))];
 const surface = () => ({
   apiPrefixes: [...realApi(), '/auth', '/landing-page-data', '/waitlist', '/sidecar'],