feat(agent-pod): add agent-hub sidecar for multi-agent session monitoring

Hub relays pi's own --mode json session protocol (session/agent_start/
turn_start/message_*/turn_end/agent_end -- the same event shape Claude
Code sessions use) to agent-console over WebSocket, so concurrent pi
runs inside the pod are observable as real transcripts instead of log
tails. agent-run.js wraps `pi -p --mode json` and relays its stdout
lines to the hub; each invocation gets its own session id, so N
concurrent agents show up as N sessions. Source mounted via ConfigMap
and run with `go run .` (no registry yet, same as the pi container).

k8s/apps/agent-pod/deployment.yaml

@@ -45,6 +45,34 @@ spec:
             - name: pi-models
               mountPath: /root/.pi/agent/models.json
               subPath: models.json
+            - name: agent-run-script
+              mountPath: /root/agent-run.js
+              subPath: agent-run.js
+        # Sidecar: relays pi's --mode json session events to agent-console.
+        # Runs via `go run` on mounted source rather than a prebuilt image --
+        # same "no registry yet" tradeoff as the pi container's npm install.
+        - name: hub
+          image: golang:1.25-alpine
+          workingDir: /hub
+          command:
+            - sh
+            - -c
+            - "go run ."
+          env:
+            - name: HUB_ADDR
+              value: ":9090"
+          ports:
+            - containerPort: 9090
+          resources:
+            requests:
+              cpu: 100m
+              memory: 128Mi
+            limits:
+              cpu: 500m
+              memory: 256Mi
+          volumeMounts:
+            - name: hub-src
+              mountPath: /hub
       volumes:
         - name: pi-config
           configMap:
@@ -52,3 +80,9 @@ spec:
         - name: pi-models
           secret:
             secretName: pi-models
+        - name: agent-run-script
+          configMap:
+            name: agent-run-script
+        - name: hub-src
+          configMap:
+            name: hub-src