Add sqlc configuration and core queries

sqlc.yaml (sqlite, schema migrations/, queries migrations/queries/)
generates internal/db with emit_interface. Queries cover dinners (create,
get, list by status, update, archive, set favorite), recipes with
ingredients and steps (upsert by source_url, get, replace children),
photos (insert, get by sha256) and get/upsert for the five settings
singletons. Repository tests run every query against a migrated temp
database.

make sqlc regenerates with the pinned sqlc v1.31.1 (dev tool only, not in
go.mod); make sqlc-check regenerates and fails on any drift in
internal/db, and CI runs it after make test.

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

migrations/queries/dinners.sql

@@ -0,0 +1,57 @@
+-- name: CreateDinner :one
+INSERT INTO dinners (
+	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
+) VALUES (
+	?, ?, ?, ?, ?, ?, ?,
+	?, ?, ?, ?, ?, ?,
+	?, ?, ?
+)
+RETURNING *;
+
+-- name: GetDinner :one
+SELECT * FROM dinners
+WHERE id = ?;
+
+-- name: ListDinnersByStatus :many
+SELECT * FROM dinners
+WHERE status = ?
+ORDER BY normalized_name, id;
+
+-- name: UpdateDinner :one
+-- An unknown id returns sql.ErrNoRows.
+UPDATE dinners
+SET name = ?,
+	normalized_name = ?,
+	status = ?,
+	origin = ?,
+	method = ?,
+	minutes_total = ?,
+	difficulty = ?,
+	cuisine = ?,
+	recipe_id = ?,
+	photo_id = ?,
+	grounding_status = ?,
+	updated_by = ?,
+	updated_at = ?
+WHERE id = ?
+RETURNING *;
+
+-- name: ArchiveDinner :one
+-- An unknown id returns sql.ErrNoRows.
+UPDATE dinners
+SET status = 'archived',
+	updated_by = ?,
+	updated_at = ?
+WHERE id = ?
+RETURNING *;
+
+-- name: SetDinnerFavorite :one
+-- An unknown id returns sql.ErrNoRows.
+UPDATE dinners
+SET is_favorite = ?,
+	updated_by = ?,
+	updated_at = ?
+WHERE id = ?
+RETURNING *;