Description

Add parsec diff [ticket] to view file changes in a worktree.

Details

• parsec diff — show diff for current worktree vs base branch
• parsec diff <ticket> — show diff for a specific ticket's worktree
• parsec diff --stat — show file-level summary only
• parsec diff --name-only — list changed file names only

Replaces

• git diff <base>..HEAD
• git diff --stat

Implementation

• Run git diff against the worktree's base branch
• Use merge-base to find correct comparison point
• Support --json output for changed file list

Priority

Medium — useful but git diff is well-known