Initial commit — DRB server stack

Includes c2-core (FastAPI/MQTT/Firestore), discord-bot (slash commands),
frontend (Next.js admin UI), and mosquitto config.

drb-c2-core/app/routers/calls.py

@@ -0,0 +1,29 @@
+from fastapi import APIRouter, HTTPException, Query
+from typing import Optional
+from app.internal import firestore as fstore
+
+router = APIRouter(prefix="/calls", tags=["calls"])
+
+
+@router.get("")
+async def list_calls(
+    node_id: Optional[str] = Query(None),
+    status: Optional[str] = Query(None),
+    system_id: Optional[str] = Query(None),
+):
+    filters = {}
+    if node_id:
+        filters["node_id"] = node_id
+    if status:
+        filters["status"] = status
+    if system_id:
+        filters["system_id"] = system_id
+    return await fstore.collection_list("calls", **filters)
+
+
+@router.get("/{call_id}")
+async def get_call(call_id: str):
+    call = await fstore.doc_get("calls", call_id)
+    if not call:
+        raise HTTPException(404, f"Call '{call_id}' not found.")
+    return call