feat: refresh agent session state on terminal switch

Add refreshAgentState() to session-state store that fetches fresh state
(hookHistory, status, etc.) via GET /session-state/{agent} from the
terminal server. Called in switchToTerminal() to ensure the UI shows
accurate hook counts when changing between terminals.

frontend/src/composables/transcript-debug/useTranscriptDebug.ts

@@ -254,6 +254,12 @@ export function useTranscriptDebug() {
       await fetchSessions()
     }
 
+    // Refresh agent session state (hookHistory, status, etc.) from server
+    const targetAgent = entry?.agent || selectedAgent.value
+    if (targetAgent) {
+      await sessionStore.refreshAgentState(targetAgent)
+    }
+
     // Load the target session's transcript (skip for __new__ — no transcript yet)
     selectedSessionId.value = transcriptSessionId
     if (transcriptSessionId === '__new__') {

frontend/src/stores/session-state.ts

@@ -1,5 +1,6 @@
 import { defineStore } from 'pinia'
 import { ref, computed } from 'vue'
+import { terminalApiUrl } from '../config/endpoints'
 
 // ── Types (mirror server/services/session-state.ts) ──
 
@@ -210,6 +211,16 @@ export const useSessionState = defineStore('session-state', () => {
     })
   }
 
+  async function refreshAgentState(agent: string) {
+    try {
+      const res = await fetch(terminalApiUrl(`/session-state/${agent}`))
+      if (!res.ok) return
+      const state = await res.json() as AgentSessionState
+      agents.value = { ...agents.value, [agent]: state }
+      lastUpdate.value = Date.now()
+    } catch { /* silent — WS patches will catch up */ }
+  }
+
   function setConnected(value: boolean) {
     connected.value = value
   }
@@ -229,6 +240,7 @@ export const useSessionState = defineStore('session-state', () => {
     hasErrors,
     visibleNotifications,
     handleMessage,
+    refreshAgentState,
     respondApproval,
     respondPlanApproval,
     setConnected,