feat: centralized PTY-scoped session state, sync engine debug panel, lifecycle states, WS monitor

- Refactor session state to use ptySessionId as primary key across all components
- Add SessionStateManager with PTY-scoped hook processing, approval tracking, notifications
- Add sync-engine debug panel (AgentStatesSection, HookTimelineSection, TerminalRegistrySection, WsMonitorSection)
- Add useLifecycleStates composable for continuous state chips (session, responding, tool, subagent, compacting)
- Add WS monitor endpoint and composable for real-time connection health
- Enhance SessionLifecycleStatus with animated state chips and badge counts
- Enhance SystemMessage with expanded content and better formatting
- Update hooks (approval-permission, approval-plan, notify) with pty_session injection
- Update approval system to derive pending lists from PTY-scoped state
- Update ChatContainer with PTY-derived agent status and lifecycle events
- Update AgentBadge with PTY-scoped status colors
- Improve PiP window, approval window, and loading window handling

hooks/notify.ps1

@@ -2,10 +2,14 @@
 # Usage: powershell -NoProfile -File hooks/notify.ps1 [agent]
 # If agent is specified, passes ?agent=<name> so the backend knows the source.
 # If omitted, the backend auto-detects from session_id/transcript_path.
+# Reads AGENT_UI_PTY_SESSION env var (injected by PTY spawn) to identify the terminal.
 param([string]$agent = "")
 $b = [Console]::In.ReadToEnd()
 $url = 'http://localhost:4101/api/claude-hook'
-if ($agent) { $url += "?agent=$agent" }
+$sep = '?'
+if ($agent) { $url += "${sep}agent=$agent"; $sep = '&' }
+$pty = $env:AGENT_UI_PTY_SESSION
+if ($pty) { $url += "${sep}pty_session=$pty" }
 try {
   Invoke-RestMethod -Uri $url -Method POST -Body $b -ContentType 'application/json' -TimeoutSec 3 | Out-Null
 } catch {}