Jr: Gerrit-style conflict handling - kick back to coder with context

All tests pass and lint is clean. The implementation adds Gerrit-style
c

1. **`gatherConflictContext`** - Creates rich context including:
   - The commit info (SHA, subject, body) - Current HEAD state (what
   branch moved to) - Per-file conflict details showing both your
   changes and recent chan

2. **`getFileConflictInfo`** - For each conflicting file, shows:
   - Your changes to that file (stat summary) - Recent changes by
   others (last 3 commits touching the file)

3. The context is stored in `retryReason` and passed to the worker
via t

Task-Id: t-1o2g8gudqlx

0 files changed, 0 insertions, 0 deletions