fix: photo import language + no-recipe-recognized handling (v0.29.0)

importFromPhoto() accepted a locale param but silently discarded it
(named _locale, never read) — now builds a language instruction the
same way generate-recipe.ts does for text generation.

The AI output schema had no way to signal "couldn't find a recipe in
this image" — generateObject would always fabricate a title/fields.
Added a `found` boolean the model sets to false in that case; the
route now returns 422 instead of creating a garbage recipe and
sending the user into the editor with it.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

apps/web/app/api/v1/ai/import-photo/route.ts

@@ -44,6 +44,10 @@ export async function POST(req: NextRequest) {
   if (!result.ok) return result.response;
   const recipe = result.data;
 
+  if (!recipe.found) {
+    return NextResponse.json({ error: "No recipe recognized in photo" }, { status: 422 });
+  }
+
   const newRecipeId = crypto.randomUUID();
   const now = new Date();