feat: guided diagnostic session (CLI) — pick a game, capture, analyze — 0.11.0

The seed use case end to end, orchestrating M3 + M4 (ARCHITECTURE §7.1).

- core/diagnostic.py: start(game) runs a focused, game-tagged capture into a
  dedicated diagnostic log (window-scoped report, separate from the always-on
  crash log); finish() stops it and combines the capture summary (M3) with the
  health findings (M4). Game recorded as a log event so it survives crash+reboot.
- CLI: rigdoctor diagnose start --game/--appid | status | finish.
- recorder/record run gained an optional --game tag; reccontrol passes it through.
- Tests for game recovery + the finish() combination.

GUI/tray "Run Diagnostic" button and auto start/stop (D12 wrapper) come next.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

docs/ROADMAP.md

@@ -40,8 +40,11 @@ Ubuntu + NVIDIA first; `.deb` distribution (see `DECISIONS.md`).
 - [ ] M10 desktop GUI (PySide6: dashboard, log browser, report viewer, logger controls)
 - [ ] M11 tray / menu-bar applet (QSystemTrayIcon: live M1 readouts + Run Diagnostic +
       supporting actions — D13)
-- [ ] Guided diagnostic session (pick game → focused M3 capture → M4 scan → findings),
-      shared by tray/GUI/CLI
+- [~] Guided diagnostic session (pick game → focused M3 capture → M4 scan → findings),
+      shared by tray/GUI/CLI — *core + CLI done* (`core/diagnostic.py`, `rigdoctor diagnose
+      start/status/finish`): tags a focused capture with the chosen game (own diagnostic log,
+      window-scoped report) and combines the capture summary with the M4 findings. *Pending:*
+      the GUI/tray "Run Diagnostic" button, and auto start/stop via the D12 wrapper/watcher.
 - [ ] Logger trigger modes: always-on + game-launch (D12 — wrapper first:
       `rigdoctor wrap %command%` + global Steam compat-tool; zero-config watcher
       (Steam RunningAppID + /proc) and GameMode hook follow)