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/App.tsx

@@ -34,6 +34,7 @@ import BackToTop from "./components/ui/BackToTop";
 import PageShell from "./components/ui/PageShell";
 import GlassTuner from "./components/GlassTuner";
 import ChatDock from "./components/ChatDock";
+import DebugRecorder from "./components/DebugRecorder";
 import Toaster from "./components/ui/Toaster";
 import KeyboardHelp from "./components/ui/KeyboardHelp";
 import AppCommandPalette from "./components/AppCommandPalette";
@@ -147,12 +148,18 @@ export default function App() {
   );
 
   // The account's consented diagnostics level (E22 S5), applied to this tab's log: raised, the log is
-  // kept in more detail and streamed to the server until the level lapses. A lapse (its own timer, or
-  // the server saying it is off) refetches `me`, so Settings shows the base level again.
+  // kept in more detail and streamed to the server until the level lapses. A debug session that is
+  // recording (E16) raises it for its own run and tags what it keeps. A lapse (its own timer, or the
+  // server saying it is off) refetches `me`, so Settings and the recorder show what is in force.
   const diagnostics = meQuery.data?.diagnostics;
+  const debugSession = meQuery.data?.debug_session;
   useEffect(() => {
-    applyDiagnostics(diagnostics, () => void queryClient.invalidateQueries({ queryKey: qk.me() }));
-  }, [diagnostics?.level, diagnostics?.until]); // eslint-disable-line react-hooks/exhaustive-deps
+    applyDiagnostics(
+      diagnostics,
+      debugSession,
+      () => void queryClient.invalidateQueries({ queryKey: qk.me() }),
+    );
+  }, [diagnostics?.level, diagnostics?.until, debugSession?.id, debugSession?.ended_at]); // eslint-disable-line react-hooks/exhaustive-deps
 
   // Fetch the code of every module this account can open — and the channel page — once the first page
   // is on screen, so a module's first visit renders at once instead of flashing the chunk fallback.
@@ -411,6 +418,8 @@ export default function App() {
       <KeyboardHelp />
       <AppCommandPalette />
       {meQuery.data && !meQuery.data.is_demo && <ChatDock meId={meQuery.data.id} />}
+      {/* The debug recorder (E16): its start dialog, and its pill docked under the toasts. */}
+      {meQuery.data && !meQuery.data.is_demo && <DebugRecorder />}
       <Suspense fallback={null}>
         {aboutOpen && (
           <About