Release 0.0.8: periodic update checks + "Run with admin" health checks

- GUI re-checks for new releases while running (every update_check_minutes,
  default 30; 0 disables), so a newly published version is detected without a
  restart; re-checks pause after an update is applied (awaiting restart)
- Health page "Run with admin" button: runs all checks incl. root-only SMART
  via `pkexec rigdoctor report --json`, so the full report is available from the
  UI (cancel keeps prior results)
- version 0.0.8, CHANGELOG

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

CHANGELOG.md

@@ -5,6 +5,15 @@ All notable changes to RigDoctor are recorded here. Format follows
 (`MAJOR.MINOR.PATCH`, pre-1.0). `__version__` and `pyproject.toml` must match the git
 release tag (so the auto-updater, D18, can compare versions).
 
+## [0.0.8] - 2026-05-21
+### Added
+- **Periodic update checks**: the GUI now re-checks for new releases while running (every
+  `update_check_minutes`, default 30; 0 disables), so a newly published version is detected
+  without restarting. After applying an update, re-checks stop until restart.
+- **"Run with admin" on the Health page**: runs all checks (including root-only SMART) via
+  `pkexec rigdoctor report --json`, so the full report — not just "SMART needs root" — is
+  available from the UI.
+
 ## [0.0.7] - 2026-05-21
 ### Added
 - **User-local installer** `install.sh` (no root): creates a private venv, links