Make recipe repairs conditional and keep pasted links out of logs

F1: A candidate or link repair now writes the dinner only if it is still
unarchived and as observed before grounding (normalized_name,
grounding_status, grounding_revision and recipe_id). A dinner renamed or
grounded some other way meanwhile is ErrGroundConflict (409
ground_conflict); one archived, before or during the repair, is
ErrArchived (409 dinner_archived). Manual repairs reject archived dinners
too.

F2: Any failure grounding a candidate or link by hand wraps
ErrGroundFailed, which the API logs as reason=ground_failed with the
dinner id only, never the pasted link or dependency error text.
GroundURL no longer formats the link into its error.

Maestro task 8741cedb-1849-4e3f-8d05-f5648c77c7ee.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

migrations/queries/dinners.sql

@@ -84,19 +84,28 @@ RETURNING *;
 -- name: GroundDinner :one
 -- Records a dinner's grounding by hand (grounded or manual) and clears any
 -- grounding_error and pasted recipe_url: the recipe chosen replaces the
--- link. An unknown id returns sql.ErrNoRows.
+-- link. It writes only an unarchived dinner still as it was observed
+-- before grounding (same normalized_name, grounding_status,
+-- grounding_revision and recipe_id), so a dinner renamed, archived or
+-- grounded some other way meanwhile is left as it is. That dinner, or an
+-- unknown id, returns sql.ErrNoRows.
 UPDATE dinners
-SET recipe_id = ?,
+SET recipe_id = sqlc.arg(recipe_id),
 	recipe_url = NULL,
-	photo_id = ?,
-	method = ?,
-	minutes_total = ?,
-	difficulty = ?,
-	grounding_status = ?,
+	photo_id = sqlc.arg(photo_id),
+	method = sqlc.arg(method),
+	minutes_total = sqlc.arg(minutes_total),
+	difficulty = sqlc.arg(difficulty),
+	grounding_status = sqlc.arg(grounding_status),
 	grounding_error = NULL,
-	updated_by = ?,
-	updated_at = ?
-WHERE id = ?
+	updated_by = sqlc.arg(updated_by),
+	updated_at = sqlc.arg(updated_at)
+WHERE id = sqlc.arg(id)
+	AND status <> 'archived'
+	AND normalized_name = sqlc.arg(observed_normalized_name)
+	AND grounding_status = sqlc.arg(observed_grounding_status)
+	AND grounding_revision = sqlc.arg(observed_grounding_revision)
+	AND recipe_id IS sqlc.narg(observed_recipe_id)
 RETURNING *;
 
 -- name: GroundPendingDinner :execrows