Add uv.lock to .gitignore

[nikblanchet]

Problem

The uv.lock file is not in .gitignore and is showing up as an untracked file in worktrees.

Context

• uv.lock is not committed in main
• uv.lock is not in .gitignore
• The project appears to intentionally not use lockfiles (no lockfile in main worktree)

Per UV best practices:

• Applications: Commit lockfile for reproducible builds
• Libraries: Gitignore lockfile to let consumers resolve

Since this project doesn't currently commit the lockfile, we should add it to .gitignore for consistency.

Solution

Add to .gitignore:

# UV lockfile (not committed - let uv resolve fresh)
uv.lock

Alternative

If reproducible builds are desired, commit uv.lock instead of gitignoring it. This would require generating and committing the lockfile.