fix(rebase): remove duplicate definitions and update stale module paths

Rebase left duplicate function blocks in worker.py (triple human_message
write causing 3x user messages in /history), deps.py, and prompt.py.
Also update checkpointer imports from the old deerflow.agents.checkpointer
path to deerflow.runtime.checkpointer, and clean up orphaned feedback
props in the frontend message components.

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

backend/app/gateway/deps.py

@@ -137,36 +137,6 @@ def get_run_context(request: Request) -> RunContext:
     )
 
 
-async def get_current_user(request: Request) -> str | None:
-    """Extract user identity from request.
-
-    Phase 2: always returns None (no authentication).
-    Phase 3: extract user_id from JWT / session / API key header.
-    """
-    return None
-
-
-get_thread_meta_repo = _require("thread_meta_repo", "Thread metadata store")
-
-
-def get_run_context(request: Request) -> RunContext:
-    """Build a :class:`RunContext` from ``app.state`` singletons.
-
-    Returns a *base* context with infrastructure dependencies.  Callers that
-    need per-run fields (e.g. ``follow_up_to_run_id``) should use
-    ``dataclasses.replace(ctx, follow_up_to_run_id=...)`` before passing it
-    to :func:`run_agent`.
-    """
-    from deerflow.config import get_app_config
-
-    return RunContext(
-        checkpointer=get_checkpointer(request),
-        store=get_store(request),
-        event_store=get_run_event_store(request),
-        run_events_config=getattr(get_app_config(), "run_events", None),
-        thread_meta_repo=get_thread_meta_repo(request),
-    )
-
 
 # ---------------------------------------------------------------------------
 # Auth helpers (used by authz.py and auth middleware)