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>

docs/DECISIONS.md

@@ -191,7 +191,11 @@ desirable — access control is delegated to Gitea.
 PATCH for ordinary changes, MINOR for larger milestones). `__version__`
 (`rigdoctor/__init__.py`) and `pyproject.toml` are the single source of truth and **must match
 the git release tag** so the auto-updater (D18) can compare versions. Every change updates
-`CHANGELOG.md` — now generated from **Conventional Commits** via git-cliff (see D20). *Note:* an early placeholder `0.1.0` was corrected to
+`CHANGELOG.md` — now generated from **Conventional Commits** via git-cliff (see D20).
+*Milestone policy (pre-1.0):* **0.0.x** = early development; **0.1.0** = first complete,
+installable, self-updating release (reached 2026-05-21); **0.x.0** = each later milestone
+(AMD/Intel, unattended logger auto-start, session sharing…); **1.0.0** = broadly stable
+(multi-vendor/distro, no major caveats). PATCH (`0.x.PATCH`) for fixes/small changes. *Note:* an early placeholder `0.1.0` was corrected to
 follow the released **0.0.x** line — first release was **V0.0.1**; current is **0.0.2**.
 
 ### D20 — Automated changelog & release notes — *DECIDED 2026-05-21*
@@ -206,9 +210,22 @@ follow the released **0.0.x** line — first release was **V0.0.1**; current is
 - *CI does not auto-commit the changelog* (avoids push loops) — it's regenerated by the dev
   via the script when cutting a version; CI only reads the section for the release body.
 
+### D21 — Versioning rules & automation — *DECIDED 2026-05-21*
+The next version is **determined by the Conventional Commit types** since the last release
+(D20), so it can be auto-computed instead of guessed:
+- `fix:` / `perf:` → bump **PATCH**.
+- `feat:` → bump **MINOR** (pre-1.0: `0.MINOR.0`).
+- breaking (`feat!:` / `BREAKING CHANGE:`) → pre-1.0: bump **MINOR** (not major); post-1.0: MAJOR.
+- `docs:` / `chore:` / `refactor:` / `ci:` / `test:` / `style:` alone → **PATCH** (no feature release).
+- Milestone overrides by hand are allowed (e.g., jumping to `1.0.0`); see the milestone policy in D19.
+
+*Automation:* `git-cliff --bumped-version` computes the next version from history;
+`packaging/bump.sh` writes it into `__init__.py` + `pyproject.toml`. Rules live in
+`cliff.toml [bump]` (pre-1.0: `breaking_always_bump_major = false`).
+
 ## Open
 
-None currently — all tracked decisions (D1–D20) are resolved. New questions will be added
+None currently — all tracked decisions (D1–D21) are resolved. New questions will be added
 here as they arise. Remaining detail to flesh out during build: the tray's supporting-action
 set (D13), per-module apt package names, M12's tunnel/token specifics, and M13's
 update mechanism (APT repo vs. self-installed `.deb`).