feat(host-agent): Backend-Anbindung — RVS + Bridge-Registry + Brain-Tools (Phase B-D)

Damit kann ARIA Host-Agenten tatsaechlich nutzen (Ende-zu-Ende):

- RVS: host_hello/host_ping/host_command/host_result in ALLOWED_TYPES.
- Bridge: _hosts-Registry (host_hello/host_ping/host_result), _host_list,
  _host_request (requestId->Future wie Satelliten), HTTP-Endpoints
  /internal/host-list und /internal/host (op via action).
- Brain: Tools host_list/host_exec/host_read/host_write/host_info/
  host_screenshot + _dispatch_host (ruft /internal/host*). host_screenshot
  speichert das PNG unter /shared/host-screenshots. host_exec kann sudo=true.

Naechste (optionale) Phase E: Host-Agenten in der Diagnostic-Flotte anzeigen.

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

bridge/aria_bridge.py

@@ -766,6 +766,11 @@ class ARIABridge:
         # requestId → Future (sat_devices / sat_result), analog _pending_flux.
         self._satellites: dict[str, dict] = {}
         self._pending_sat: dict[str, asyncio.Future] = {}
+        # Host-Agenten (Direktzugriff auf einen Rechner). hostId → {name, os,
+        # caps, control, last_seen}. Registrierung via host_hello/host_ping.
+        # _pending_host: requestId → Future (host_result), analog _pending_sat.
+        self._hosts: dict[str, dict] = {}
+        self._pending_host: dict[str, asyncio.Future] = {}
         # Compute-Fleet: GPU-Worker (voxtral/whisper/f5tts/llm) melden sich per
         # worker_hello, halten sich per worker_ping frisch. instanceId →
         # {service, node, gpus, model, busy, last_seen}. Genutzt fuer die
@@ -3550,6 +3555,40 @@ class ARIABridge:
                             self._satellites[sid]["caps"], self._satellites[sid]["control"])
             return
 
+        elif msg_type == "host_hello":
+            hid = (payload.get("hostId") or "").strip()
+            if hid:
+                new = hid not in self._hosts
+                self._hosts[hid] = {
+                    "hostId": hid,
+                    "name": payload.get("name") or hid,
+                    "os": payload.get("os") or "",
+                    "caps": payload.get("caps") or [],
+                    "control": bool(payload.get("control")),
+                    "last_seen": time.time(),
+                }
+                if new:
+                    logger.info("[host] Agent online: %s (%s) caps=%s control=%s",
+                                hid, self._hosts[hid]["name"],
+                                self._hosts[hid]["caps"], self._hosts[hid]["control"])
+            return
+
+        elif msg_type == "host_ping":
+            hid = (payload.get("hostId") or "").strip()
+            if hid and hid in self._hosts:
+                self._hosts[hid]["last_seen"] = time.time()
+            return
+
+        elif msg_type == "host_result":
+            req_id = payload.get("requestId", "")
+            future = self._pending_host.get(req_id)
+            if future is not None and not future.done():
+                future.set_result(payload)
+            hid = (payload.get("hostId") or "").strip()
+            if hid and hid in self._hosts:
+                self._hosts[hid]["last_seen"] = time.time()
+            return
+
         elif msg_type == "worker_hello":
             iid = (payload.get("instanceId") or "").strip()
             if iid:
@@ -4523,6 +4562,24 @@ class ARIABridge:
                 elif method in ("GET", "POST") and path == "/internal/worker-list":
                     # Diagnostic/Brain fragt: welche Compute-Worker sind online (Flotte).
                     await _send_response(writer, 200, {"ok": True, "workers": self._worker_list()})
+                elif method == "POST" and path == "/internal/host-list":
+                    # Brain fragt: welche Host-Agenten (Rechner) sind online + Capabilities.
+                    await _send_response(writer, 200, {"ok": True, "hosts": self._host_list()})
+                elif method == "POST" and path == "/internal/host":
+                    # Brain-Tool: Kommando an einen Host-Agenten.
+                    # body: {host, action, params?, timeout?}
+                    try:
+                        data = json.loads(body.decode("utf-8", "ignore"))
+                    except Exception as exc:
+                        await _send_response(writer, 400, {"error": f"bad json: {exc}"})
+                        return
+                    result = await self._host_request(
+                        host=str(data.get("host") or ""),
+                        action=str(data.get("action") or ""),
+                        params=data.get("params") if isinstance(data.get("params"), dict) else {},
+                        timeout=float(data.get("timeout") or 60.0),
+                    )
+                    await _send_response(writer, 200, result)
                 elif method == "POST" and path == "/internal/satellite":
                     # Brain-Tool: Discovery oder Command an einen Satelliten.
                     # body: {op:'discover'|'command', satellite, device?, action?, params?}
@@ -4862,6 +4919,44 @@ class ARIABridge:
         finally:
             self._pending_sat.pop(request_id, None)
 
+    def _host_list(self) -> list[dict]:
+        """Bekannte Host-Agenten (frisch = in den letzten 5 Min gesehen)."""
+        now = time.time()
+        return [{
+            "hostId": h["hostId"], "name": h.get("name") or h["hostId"],
+            "os": h.get("os") or "", "caps": h.get("caps") or [],
+            "control": bool(h.get("control")),
+            "online": (now - h.get("last_seen", 0)) < 300,
+        } for h in self._hosts.values()]
+
+    async def _host_request(self, host: str = "", action: str = "",
+                            params: Optional[dict] = None,
+                            timeout: float = 60.0) -> dict:
+        """Schickt host_command an einen Host-Agenten (via RVS) und wartet auf
+        host_result. Muster identisch zu _satellite_request."""
+        if self.ws_rvs is None:
+            return {"ok": False, "error": "RVS-Verbindung nicht aktiv"}
+        request_id = str(uuid.uuid4())
+        loop = asyncio.get_event_loop()
+        future: asyncio.Future = loop.create_future()
+        self._pending_host[request_id] = future
+        try:
+            msg = {"type": "host_command",
+                   "payload": {"requestId": request_id, "host": host,
+                               "action": action, "params": params or {}},
+                   "timestamp": int(time.time() * 1000)}
+            ok = await self._send_to_rvs(msg)
+            if not ok:
+                return {"ok": False, "error": "Host-Request konnte nicht gesendet werden"}
+            result = await asyncio.wait_for(future, timeout=timeout)
+            return result if isinstance(result, dict) else {"ok": False, "error": "ungueltige Antwort"}
+        except asyncio.TimeoutError:
+            return {"ok": False, "error": f"Host '{host or 'all'}' antwortet nicht (Timeout)."}
+        except Exception as exc:
+            return {"ok": False, "error": str(exc)}
+        finally:
+            self._pending_host.pop(request_id, None)
+
     async def _delete_chat_message(self, ts: int) -> dict:
         """Entfernt eine Bubble: aus chat_backup.jsonl + Brain conversation,
         broadcastet chat_message_deleted via RVS.