feat: Prompts Atomic PR of #20243 (#20368)

* feat: Add read-only access support for Prompts

- Backend: Add write_access field to PromptAccessResponse
- Backend: Update /prompts/list to return prompts with write_access
- Frontend: Display Read Only badge in Prompts list
- Frontend: Disable inputs and save button when no write access

* feat: Add read-only visual indicators for Prompts workspace

* fix: Return write_access from getPromptByCommand endpoint

- Backend returns write_access directly in response
- Frontend extracts write_access from getPromptByCommand response
- Remove inefficient getPromptList call in edit page

* fix: Align Read Only badge to right in Prompts.svelte

- Title and command stay on left
- Badge pushed to right by justify-between

* fix: Use PromptAccessResponse in get_prompt_by_command endpoint

fix: Use PromptAccessResponse in get_prompt_by_command endpoint

- Return PromptAccessResponse Pydantic model instead of raw dict
- Properly type the response with response_model

backend/open_webui/models/prompts.py

@@ -64,6 +64,10 @@ class PromptUserResponse(PromptModel):
     user: Optional[UserResponse] = None
 
 
+class PromptAccessResponse(PromptUserResponse):
+    write_access: Optional[bool] = False
+
+
 class PromptForm(BaseModel):
     command: str
     title: str