git add -A and git clean -fd in ratchet loop can destroy unrelated work in the repo

[consigcody94]

Summary

Found via code audit. The ratchet loop's git operations are overly aggressive and can destroy unrelated user work.

Bug 1: `git add -A` stages ALL files (HIGH)

File: `recursive_improve/ratchet/git_ops.py`, line 27

The ratchet loop blindly stages ALL files. If a user has unrelated drafts, data files, or `.env` files, they get committed.

Bug 2: `git clean -fd` deletes untracked files on revert (HIGH)

File: `recursive_improve/ratchet/git_ops.py`, lines 45-47

On revert, `git checkout -- .` + `git clean -fd` destroys all untracked files in the repo.

Fix: Track which files the improvement step touched and only stage/revert those specific files.

Bug 3: Git commands silently succeed on error (MEDIUM)

File: `recursive_improve/ratchet/git_ops.py`, lines 20-24

`git status --porcelain` result is never checked for errors. If git is not installed or the directory is not a repo, the function silently returns None (as if nothing needs committing), losing changes.

Fix: Add `check=True` or verify `result.returncode == 0`.

Found via code audit.