Guard recipe repairs against same-normalized renames and member edits

F1-1: GroundDinner also compares the observed raw name, so renaming
"Grandma's stew" to "Easy Grandma's stew" (same normalized_name) while a
link is grounding is ErrGroundConflict, not attached to the renamed
dinner.

F1-2: A method, minutes_total or difficulty no longer as observed before
grounding is kept over the recipe's value, as GroundPendingDinner keeps
values a member set while a dinner was pending.

F2-1: Failing to record a grounded candidate or link on the dinner (or to
read it back after a rejected write) wraps ErrGroundFailed, so the API
logs reason=ground_failed with the dinner id, never the database error.

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

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

internal/db/dinners.sql.go

@@ -251,32 +251,40 @@ UPDATE dinners
 SET recipe_id = ?1,
 	recipe_url = NULL,
 	photo_id = ?2,
-	method = ?3,
-	minutes_total = ?4,
-	difficulty = ?5,
-	grounding_status = ?6,
+	method = CASE WHEN method IS ?3
+		THEN ?4 ELSE method END,
+	minutes_total = CASE WHEN minutes_total IS ?5
+		THEN ?6 ELSE minutes_total END,
+	difficulty = CASE WHEN difficulty IS ?7
+		THEN ?8 ELSE difficulty END,
+	grounding_status = ?9,
 	grounding_error = NULL,
-	updated_by = ?7,
-	updated_at = ?8
-WHERE id = ?9
+	updated_by = ?10,
+	updated_at = ?11
+WHERE id = ?12
 	AND status <> 'archived'
-	AND normalized_name = ?10
-	AND grounding_status = ?11
-	AND grounding_revision = ?12
-	AND recipe_id IS ?13
+	AND name = ?13
+	AND normalized_name = ?14
+	AND grounding_status = ?15
+	AND grounding_revision = ?16
+	AND recipe_id IS ?17
 RETURNING id, name, normalized_name, status, origin, method, minutes_total, difficulty, cuisine, is_favorite, recipe_id, photo_id, grounding_status, updated_by, created_at, updated_at, recipe_url, grounding_error, grounding_revision
 `
 
 type GroundDinnerParams struct {
 	RecipeID                  sql.NullString
 	PhotoID                   sql.NullString
+	ObservedMethod            sql.NullString
 	Method                    sql.NullString
+	ObservedMinutesTotal      sql.NullInt64
 	MinutesTotal              sql.NullInt64
+	ObservedDifficulty        sql.NullString
 	Difficulty                sql.NullString
 	GroundingStatus           string
 	UpdatedBy                 sql.NullString
 	UpdatedAt                 string
 	ID                        string
+	ObservedName              string
 	ObservedNormalizedName    string
 	ObservedGroundingStatus   string
 	ObservedGroundingRevision int64
@@ -286,21 +294,26 @@ type GroundDinnerParams struct {
 // 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. It writes only an unarchived dinner still as it was observed
-// before grounding (same normalized_name, grounding_status,
+// before grounding (same name, 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.
+// unknown id, returns sql.ErrNoRows. A method, minutes_total or difficulty
+// no longer as observed is kept: a member edited it while it was grounding.
 func (q *Queries) GroundDinner(ctx context.Context, arg GroundDinnerParams) (Dinner, error) {
 	row := q.db.QueryRowContext(ctx, groundDinner,
 		arg.RecipeID,
 		arg.PhotoID,
+		arg.ObservedMethod,
 		arg.Method,
+		arg.ObservedMinutesTotal,
 		arg.MinutesTotal,
+		arg.ObservedDifficulty,
 		arg.Difficulty,
 		arg.GroundingStatus,
 		arg.UpdatedBy,
 		arg.UpdatedAt,
 		arg.ID,
+		arg.ObservedName,
 		arg.ObservedNormalizedName,
 		arg.ObservedGroundingStatus,
 		arg.ObservedGroundingRevision,

internal/db/querier.go

@@ -70,10 +70,11 @@ type Querier interface {
 	// 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. It writes only an unarchived dinner still as it was observed
-	// before grounding (same normalized_name, grounding_status,
+	// before grounding (same name, 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.
+	// unknown id, returns sql.ErrNoRows. A method, minutes_total or difficulty
+	// no longer as observed is kept: a member edited it while it was grounding.
 	GroundDinner(ctx context.Context, arg GroundDinnerParams) (Dinner, error)
 	// Records the background grounding of an unarchived dinner still pending at
 	// the grounding_revision it was grounded for; a dinner grounded some other