v0.27.0 — Code screen completed: git, accept/discard, live per-edit diffs

This rounds out the Code screen — the verify-or-revert coding front — with the pieces that make it a real workflow. Grounded in real backend data; the terminal stays sovereign.

Added

• Git panel — real git status (branch + staged/modified/untracked), per-file git diff (real hunks), and commit. Thin wrappers over the existing git plumbing; every call gated on is_git_repo first (git missing or non-repo → honest empty-state, never a crash). Commit stages the explicitly-selected paths only — never git add -A.
• Accept / discard a run's changes — after a coding run, Accept keeps the changes (already on disk); Discard reverts them via git, scoped to the run's files (git checkout the tracked subset + git clean the in-scope new files). Enabled only in a git repo, honestly disabled and explained otherwise; it reverts only what git can see.
• Live per-edit diffs — during a run, the screen streams the real unified diff of each file the agent edits, the moment it edits it, alongside the final receipt diffs. Captured by reading the file before/after each write-tool call (single-threaded, so it's exact for every write tool — including whole-file overwrites); a no-op edit shows nothing. It rides a new on_edit/edit event through the solve loop, so chimera solve's event sink gets it too.

pip install -U 'chimera-agent[desktop]' → chimera app. 7 UI languages, localhost-only, bearer-guarded.

Full changelog: https://github.com/brcampidelli/chimera-agent/blob/main/CHANGELOG.md