Plan task P1.6. Modal hold-creation form: reason picker, qty split,
optional photo (camera input on mobile), description, mark-for-scrap
toggle. Calls /fp/workspace/hold (added in P1.9). Reason list kept
client-side, keep in sync with fusion.plating.quality.hold.hold_reason.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>