feat: add image_path to recipe/subtask and user password change API

- Recipe model: add image_path field for recipe-level image
- RecipeSubtask model: add image_path for per-subtask detail images
- Schemas: add image_path to create/update/response for recipe and subtask
- Task router: pass image_path when creating tasks and subtasks
- Recipe service: copy image_path in versioning and update-in-place
- Users router: add PUT /{user_id}/password endpoint (admin only)
- User schema: add UserPasswordChange model

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/services/recipe_service.py

@@ -77,6 +77,7 @@ async def _copy_tasks_to_version(
                 lwl=sub.lwl,
                 ltl=sub.ltl,
                 unit=sub.unit,
+                image_path=sub.image_path,
             )
             db.add(new_sub)
 
@@ -132,6 +133,7 @@ async def create_recipe(
         code=data.code,
         name=data.name,
         description=data.description,
+        image_path=data.image_path,
         created_by=user.id,
     )
     db.add(recipe)
@@ -285,6 +287,8 @@ async def create_new_version(
         update_fields["name"] = data.name
     if data.description is not None:
         update_fields["description"] = data.description
+    if data.image_path is not None:
+        update_fields["image_path"] = data.image_path
     if update_fields:
         await db.execute(
             update(Recipe).where(Recipe.id == recipe_id).values(**update_fields)
@@ -373,12 +377,14 @@ async def update_current_version(
     data: RecipeUpdate,
 ) -> RecipeVersion:
     """Update recipe header in-place on the current version (no copy-on-write)."""
-    # Apply header updates (name, description)
+    # Apply header updates (name, description, image_path)
     update_fields: dict = {}
     if data.name is not None:
         update_fields["name"] = data.name
     if data.description is not None:
         update_fields["description"] = data.description
+    if data.image_path is not None:
+        update_fields["image_path"] = data.image_path
     if update_fields:
         await db.execute(
             update(Recipe).where(Recipe.id == recipe_id).values(**update_fields)