Release v0.51

Release v0.51 — incremental update from v0.50 with 36 merged PRs.

🐛 Bug Fixes

#1565: fix(install): use --version flag, cobra has no version subcommand
#1564: fix(uninstall): sudo hint uses full binary path, docs warn against sudo
#1561: fix(docker): guard workspace npm install on .package-lock.json, not node_modules dir
#1554: feat(#1517): [Bug] Cheasee-pi operating instructions live in project-scoped AGENTS.md and are absent in non-cheasee-pi repos
#1553: feat(#1529): [Bug] web_crawl stealth tier fails: Chromium missing in /opt/playwright-browsers (patchright revision 1228 never installed)
#1552: fix(web_crawl): patchright chromium install, worktree venv symlinks, scrapling e2e tests
#1551: feat(#1495): [Bug] PR overview table documents only one run when agent is retried (developer ran twice in #1494)
#1520: fix(clean): reap detached docker exec pi sessions by age + marker
#1518: fix(supervisor): fall back to tmpdir when worktree base is not writable
#1515: fix(structural-search): honor directory param in ast-grep search
#1514: fix(supervisor): truthful worktree-creation failure — fixes 'Worktree missing' cascade and rtk false warning
#1512: fix(supervisor): crash when supervisor config missing
#1511: fixes

#1550: feat(#1509): [Feature] Add rebuild command: full image rebuild without cache plus prune
#1549: feat(#1526): [Feature] Per-issue supervisor run lock: restore parallel pipelines on different issues
#1530: feat(#1510): [Feature] Standalone uninstall script alongside install.sh
#1528: feat(#1507): [Feature] Ask for custom skill repositories during init and install via pi's git package mechanism
#1524: feat(#1503): [Feature] Per-repository container identity with parallel coexistence
#1523: feat(#1505): [Feature] init on an initialized workspace redoes git and pi authentications
#1522: feat(#1506): [Feature] Scaffold workspace settings with all defaults incl. repo URL and pre-create .pi folder skeleton
#1521: feat(#1504): [Feature] One-shot first run: init, build and start pi in a single invocation
#1516: feat(#1503): Per-repository container identity with parallel coexistence
#1502: feat(#1499): [Feature] Run cheasee-pi from empty folder: auto-init with worktree setup and dedicated cheasee-settings.json
#1501: feat(#1497): [Feature] Fix resource duplication when running cheasee-pi on itself (dogfooding)
#1500: feat(#1496): Remove generated repo-root docker/ tree and sync machinery after #1493
#1498: feat(#1493): [Feature] Run cheasee-pi from user's own git repository; bake cheasee-pi repo into pi installation
#1494: feat(#1492): Remove all git submodules — cheasee-pi becomes single normal repo

Full Changelog: v0.50...v0.51