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/models/recipe.py

@@ -18,6 +18,7 @@ class Recipe(Base):
     code: Mapped[str] = mapped_column(String(100), unique=True, nullable=False, index=True)
     name: Mapped[str] = mapped_column(String(255), nullable=False)
     description: Mapped[Optional[str]] = mapped_column(Text, nullable=True)
+    image_path: Mapped[Optional[str]] = mapped_column(String(500), nullable=True)
     created_by: Mapped[int] = mapped_column(Integer, ForeignKey("users.id"), nullable=False)
     created_at: Mapped[datetime] = mapped_column(
         DateTime, nullable=False, server_default=func.now()