feat(diagnostic): Agent-Historie pro Agent — Akkordeon je Nachricht

Jede Host-Aktion wird als Historie-Eintrag festgehalten und in der Diagnostic
pro User-Nachricht gruppiert aufklappbar dargestellt (mit Screenshot-Thumbnails).

- Brain: trace_id+msg pro chat(); _dispatch_host als Wrapper um _dispatch_host_inner
  emittiert je Aktion einen Eintrag an POST /internal/agent-history (Datei-Pfad aus
  Screenshot-Text erkannt).
- Bridge: /internal/agent-history persistiert nach /shared/config/agent_history/
  <hostId>.jsonl (Ringpuffer 200) + broadcastet agent_history; agent_history_query
  -> agent_history_list.
- RVS: agent_history/_query/_list in ALLOWED_TYPES (sonst still verworfen).
- Diagnostic-Server: relay browser<->RVS + /uploads/<file> Bild-Endpoint (nur
  /shared/uploads, kein Traversal).
- index.html: 'Historie'-Button je Host, Modal mit Akkordeon (Gruppe=Nachricht,
  aufklappbar, Screenshot-Thumbs), Live-Refresh bei agent_history.

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

diagnostic/server.js

@@ -1098,6 +1098,10 @@ function connectRVS(forcePlain) {
       } else if (msg.type === "rooms_info") {
         // Antwort des RVS auf rooms_query → an den Browser (Raum-Diagnose).
         broadcast({ type: "rooms_info", payload: msg.payload || {} });
+      } else if (msg.type === "agent_history" || msg.type === "agent_history_list") {
+        // Live-Event (agent_history) bzw. Abfrage-Antwort (agent_history_list)
+        // der Bridge → an den Browser (Agent-Historie).
+        broadcast({ type: msg.type, payload: msg.payload || {} });
       } else if (msg.type === "sat_devices") {
         // Antwort eines Satelliten auf sat_discover → Geraeteliste an Browser.
         const p = msg.payload || {};
@@ -1944,6 +1948,19 @@ const server = http.createServer((req, res) => {
       "Expires": "0",
     });
     res.end(fs.readFileSync(htmlPath, "utf-8"));
+  } else if (req.url.startsWith("/uploads/")) {
+    // Screenshots aus der Agent-Historie (nur /shared/uploads, kein Traversal).
+    const base = path.basename(decodeURIComponent(req.url.slice("/uploads/".length)));
+    const file = path.join("/shared/uploads", base);
+    if (!file.startsWith("/shared/uploads/") || !fs.existsSync(file)) {
+      res.writeHead(404); res.end("not found"); return;
+    }
+    const ext = path.extname(file).toLowerCase();
+    const ct = ext === ".png" ? "image/png"
+      : (ext === ".jpg" || ext === ".jpeg") ? "image/jpeg"
+      : ext === ".webp" ? "image/webp" : "application/octet-stream";
+    res.writeHead(200, { "Content-Type": ct, "Cache-Control": "max-age=86400" });
+    res.end(fs.readFileSync(file));
   } else if (req.url === "/api/state") {
     res.writeHead(200, { "Content-Type": "application/json" });
     res.end(JSON.stringify({ state, logs: logs.slice(-100) }));
@@ -2796,6 +2813,11 @@ wss.on("connection", (ws) => {
         // Browser will die RVS-Raum-Diagnose — via persistente rvsWs anfragen,
         // die Antwort (rooms_info) kommt auf derselben Verbindung zurueck.
         sendToRVS_raw({ type: "rooms_query", payload: {}, timestamp: Date.now() });
+      } else if (msg.action === "agent_history_query") {
+        // Browser will die gespeicherte Historie eines Agenten — die Bridge
+        // antwortet mit agent_history_list (auf derselben rvsWs).
+        sendToRVS_raw({ type: "agent_history_query",
+                       payload: { host: String(msg.host || "") }, timestamp: Date.now() });
       } else if (msg.action === "worker_list") {
         // Browser will die aktuelle Compute-Flotte.
         ws.send(JSON.stringify({ type: "worker_update", workers: workerList() }));