- Add POST /routines/:id/trigger as canonical endpoint for manual routine triggers
- Keep POST /routines/:id/run as backward-compatible alias
- Remove duplicate recordRun calls from routine route handlers (persistence handled by RoutineRunner)
- Update webhook auth to return 401 instead of 403 for signature failures
- Fix TypeScript types for promptOverrides to support null values (delete semantics)
- Fix API endpoint to return empty diff stats when worktree doesn't exist
