Feat: Discover zukunftssicher (Recency-Score) + Agent-Hirn (Hermes) im Modell-Manager

- discover.rank_runnable: Score aus Fit + Recency (lastModified, Halbwertszeit ~9 Mon)
  + Capability (params, log) + Popularity (downloads, log) -> neuere Generationen bevorzugt.
- Agent-Hirn: neuer GET /api/agent/brain (aktuelles hermes-Modell + bestes NousResearch-
  Hermes-Update, versions-aware via Hermes-X.Y-Parsing). Cockpit zeigt "Agent-Hirn (Hermes)"-Karte
  mit aktuellem Brain + Aktualisieren-Button, wenn NousResearch eine neuere Generation hat
  (z.B. Hermes-4-14B -> Hermes-4.3-36B). Update installiert mit Rolle hermes.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/routers/agent.py

@@ -3,7 +3,7 @@
 from fastapi import APIRouter
 from pydantic import BaseModel
 
-from services.agent import agent_status, update_brain_model
+from services.agent import agent_status, hermes_brain_info, update_brain_model
 
 router = APIRouter(prefix="/api")
 
@@ -17,6 +17,12 @@ def status() -> dict:
     return agent_status()
 
 
+@router.get("/agent/brain")
+def brain_info() -> dict:
+    """Aktuelles Agent-Hirn (hermes) + bestes NousResearch-Hermes-Update."""
+    return hermes_brain_info()
+
+
 @router.post("/agent/brain")
 def set_brain_model(body: BrainReq) -> dict:
     ok = update_brain_model(body.model)