Persist recipe English name translation to database

- Add en_name column to recipes table (migration in database.py)
- Include en_name in recipe API responses and RecipeUpdate model
- Save en_name when admin/senior_editor applies translation
- Load en_name on overlay open, so translation persists across sessions

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend/database.py

@@ -238,6 +238,8 @@ def init_db():
         c.execute("ALTER TABLE recipes ADD COLUMN owner_id INTEGER")
     if "updated_by" not in cols:
         c.execute("ALTER TABLE recipes ADD COLUMN updated_by INTEGER")
+    if "en_name" not in cols:
+        c.execute("ALTER TABLE recipes ADD COLUMN en_name TEXT DEFAULT ''")
 
     # Seed admin user if no users exist
     count = c.execute("SELECT COUNT(*) FROM users").fetchone()[0]