feat: in-app uninstaller, changelog viewer, version automation (0.1.0)

First milestone release — a complete, installable, self-updating RigDoctor:
live monitoring, crash capture + health report, desktop GUI, user-local
install/uninstall, and token-gated self-update with real release notes.

- feat(gui): in-app uninstaller — Setup "Uninstall RigDoctor" button and
  `rigdoctor uninstall [--purge]`; removes venv/launchers/desktop entry
  (detached so it can delete its own venv), with optional purge of
  settings/token/logs (core/uninstall.py)
- feat(gui): in-app changelog — sidebar "Changelog" link listing release
  history fetched from the update server (updates.list_releases)
- chore: versioning rules + automation (D21) — git-cliff --bumped-version,
  packaging/bump.sh, cliff.toml [bump] (pre-1.0: breaking -> minor)
- chore(release): stamp 0.1.0; milestone policy recorded in D19

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

cliff.toml

@@ -35,3 +35,8 @@ commit_parsers = [
 ]
 tag_pattern = "v[0-9]*"
 sort_commits = "oldest"
+
+[bump]
+# Pre-1.0 rules (D21): feat -> minor, fix -> patch, breaking -> minor (not major).
+features_always_bump_minor = true
+breaking_always_bump_major = false