Add Pydantic models and FastAPI router structure for agent and backend

backend/app/routers/discoveries.py

@@ -0,0 +1,19 @@
+from fastapi import APIRouter, HTTPException
+
+from app.schemas import DiscoveryRun, EntityResponse, ListResponse
+from app.services.store import DISCOVERY_RUNS
+
+router = APIRouter(prefix='/discoveries', tags=['discoveries'])
+
+
+@router.get('', response_model=ListResponse[DiscoveryRun])
+def list_discoveries() -> ListResponse[DiscoveryRun]:
+    return ListResponse(count=len(DISCOVERY_RUNS), items=DISCOVERY_RUNS)
+
+
+@router.get('/{discovery_id}', response_model=EntityResponse[DiscoveryRun])
+def get_discovery(discovery_id: str) -> EntityResponse[DiscoveryRun]:
+    for item in DISCOVERY_RUNS:
+        if item.id == discovery_id:
+            return EntityResponse(item=item)
+    raise HTTPException(status_code=404, detail='Discovery not found')