F1: every dinner response now carries photo_backfill_eligible, computed
by the exported dinners.PhotoBackfillEligible: the condition
ListPhotoBackfillDinners lists by and GroundFailedDinner and
RefailDinnerGrounding write under (unarchived, failed, no photo, no
pasted recipe_url). A test holds the flag to ListPhotoBackfillDinners
for an eligible dinner and for grounded, linked and archived ones. The
fix-recipe sheet shows "Search again" only when the flag is set, so a
dinner with a pasted link is never offered it, whatever its reason.
F2: a dinner absent from the backfill result now reads "This dinner was
not included in that search." instead of claiming a pasted link.
Task: 7a468d2d-4a9b-45f2-b626-a7bed5f671df
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>