feat(gui): Run Diagnostic flow on the Games page — 0.12.0

Brings the guided diagnostic (0.11.0 core/CLI) into the GUI:
- Each game row gets a "Run Diagnostic" button → starts a focused, game-tagged
  capture and shows a recording banner (live sample count + GPU-lost indicator)
  with Finish & analyze / Discard.
- Finishing runs core.diagnostic.finish() off the UI thread and opens a results
  dialog (gui/diagnostic_dialog.py): window-scoped capture summary + findings
  cards (reusing render_summary + finding_card).
- Banner restores on showEvent if a capture is still running (navigate away/back).

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

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "rigdoctor"
-version = "0.11.0"
+version = "0.12.0"
 description = "Modular hardware monitoring & crash diagnostics for Linux gamers."
 readme = "README.md"
 requires-python = ">=3.11"