feat: review agent changes by file or hunk

[opsCar]

Summary

• Capture Git working-tree changes made by each accepted agent prompt by snapshotting the selected repository scope before and after the run.
• Open a prompt-scoped Review panel when changes are detected, with file and hunk navigation plus Accept, Reject, Accept all, and Reject all actions.
• Apply review decisions transactionally with revision checks, file fingerprints, rollback, size limits, and safe file-level fallbacks for changes that cannot be reviewed by hunk.
• Bind review state to prompt run IDs so concurrent prompts and stale SSE events cannot attach changes to the wrong run.
• Re-authorize canonical allowed roots on every API operation and reject symlink escapes.

Validation

• node_modules/.bin/tsc --noEmit
• npm run lint
• node --test lib/*.test.mjs components/*.test.mjs — 117 tests passed
• git diff --check origin/main...HEAD

Notes

• Code review requires a Git repository with an initial commit.
• New, deleted, renamed, binary, mode-changing, and oversized files fall back to whole-file review when safe.
• next build was intentionally not run, following the repository development guidance.

[agegr]

Thanks for the thoughtful implementation and the attention to concurrency and safety. I don’t think this is ready to merge in its current form.

The feature is valuable, but it introduces a substantial Git review and patch-management subsystem into Pi Web. That feels heavier than the product’s current role as a web UI for Pi sessions, and it creates a large surface area around index state, conflicts, external edits, and rollback semantics. For example, rejecting a change currently restores the working tree but can leave agent-staged changes in the Git index.

I’d prefer a smaller first step, such as showing a read-only diff for changes made during a prompt. We can revisit accept/reject workflows once the desired Git semantics and long-term ownership are clearer.