chore(release): 2.1.1

[baldurpan]

Merging this publishes 2.1.1. The root version moves 2.1.0 → 2.1.1, so publish.yml runs: test, build, npm publish, tag v2.1.1, GitHub release from the CHANGELOG.md section, Discord post. A failed step is recovered with "Run workflow" (each step skips what already exists). The docs site deploys on the same merge, since docs/src/lib/site-meta.ts moves to 2.1.1.

Made with pnpm changeset:prepare-release, which consumed the six pending notes into CHANGELOG.md and synced the docs version. release-note.yml exempts this PR because the version moved.

What 2.1.1 ships (all patch):

• worktree remove and worktree cleanup remove a worktree by its path, so they no longer fail when another worktree's path ends in the branch name (fix(remove): remove a worktree by its path, not its branch name #97).
• worktree branch refuses a malformed --github/--jira id as invalid_value and exits 2 (Refuse a malformed --github/--jira issue id as invalid_value (exit 2) #96).
• worktree list --agents marks an idle or blocked interactive session as waiting (fix(list): report an idle interactive agent as waiting #95).
• worktree cleanup no longer holds back a merged worktree because an agent session in it is idle (fix(cleanup): let an idle agent session go with its merged worktree #90).
• worktree cleanup keeps a session the runtime calls done as live while its process is still running (fix(cleanup): keep a runtime-done session live while its process runs #94).
• The bundled skill states that issue content only feeds the branch name (State that issue content only feeds the branch name #93).

Verified locally on this commit: pnpm check, pnpm typecheck, pnpm build, pnpm test (1002 passed) and pnpm docs:test (68 passed) all exit 0.