feat(diagnostics): the debug recorder — start, the pill, steps, screenshots, stop (E16 S2)

- the start dialog is the consent: level (Részletes/Teljes), what is recorded,
  retention and the cap (now served as diagnostics.session_minutes)
- the pill docks under the toasts: elapsed time, Step (an optional label,
  its own Escape layer), Screenshot (tab capture where the browser has it),
  Stop; compact on a phone
- while recording, lib/log tags every event and every request path (req,
  beacon, uploadReq via one identityHeaders) names the session; applyDiagnostics
  raises the level for the session's run and never lowers a raised one, and
  lapses at whichever ends first
- Stop sends what is waiting before the server closes the session; the cap
  says so and opens the composer
- Settings → Diagnosztika and the command palette start/step/stop it
- the evidence leaves the log upload's own request lines out
- the step shortcut is deliberately palette-only: the keymap's D1 rule bars a
  new modifier chord, and a bare letter collides with the players'

frontend/src/lib/api/account.ts

@@ -1,7 +1,7 @@
 // The signed-in account & session: the bootstrap `me` probe, multi-account switch/list, sign-out,
 // app version, and preference save. Only touches core's req.
 import { req } from "./core";
-import type { DiagnosticsState } from "./diagnostics";
+import type { DebugSession, DiagnosticsState } from "./diagnostics";
 
 export interface Me {
   id: number;
@@ -33,6 +33,8 @@ export interface Me {
   preferences: Record<string, unknown>;
   /** The consented diagnostics level in force and when it lapses (E22 S5). */
   diagnostics: DiagnosticsState;
+  /** The debug session recording right now, if any (E16) — a reload resumes it. */
+  debug_session: DebugSession | null;
 }
 
 /** The `nav.role.*` key an account is shown under. Demo isn't a real role (it's a flag on a `user`