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/messages/en.json

@@ -152,6 +152,7 @@
     "cookAction": "Cook",
     "adaptConstraintPlaceholder": "e.g. Make it vegan, lower the calories, use pantry staples only, gluten-free…",
     "photoImportFailed": "Failed to import recipe from photo.",
+    "photoNoRecipeFound": "No recipe could be recognized in that photo. Try a clearer picture of the ingredients or instructions.",
     "importFromPhoto": "Import from Photo",
     "urlImportTitle": "Import recipe from URL",
     "urlImportDescription": "Paste a recipe URL and AI will extract the ingredients and instructions.",