fix: list_pending_devices MCP tool leaked approved/hidden inventory rows

The backend GET /scan/pending endpoint intentionally returns the whole
inventory — approved devices stay listed so the frontend can show the
canvas-presence badge. The MCP tool proxied that response verbatim while
its description promises devices "not yet approved or hidden", so MCP
clients saw every approved device as if it were still awaiting triage
(59 "pending" entries on a fully-triaged canvas, 58 of them approved).

Filter the tool response to status == "pending", keeping legacy rows
that predate the status field.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Udrvtwi3cqcxUNHZtBHkBg

mcp/app/tools.py

@@ -228,7 +228,12 @@ async def _dispatch(name: str, args: dict) -> dict:
         return await backend.get("/api/v1/nodes")
 
     if name == "list_pending_devices":
-        return await backend.get("/api/v1/scan/pending")
+        # Backend /scan/pending returns the whole inventory: approved rows stay
+        # listed so the frontend can show a canvas-presence badge. This tool
+        # promises only devices "not yet approved or hidden", so filter to
+        # actual pending rows (legacy rows without a status count as pending).
+        devices = await backend.get("/api/v1/scan/pending")
+        return [d for d in devices if d.get("status", "pending") == "pending"]
 
     if name == "list_designs":
         return await backend.get("/api/v1/designs")