Add ScreenConnect-parity features (high + medium)

Viewer:
- Toolbar: Ctrl+Alt+Del, clipboard paste, monitor picker, file transfer, chat, WoL buttons
- Multi-monitor: agent sends monitor_list on connect, viewer can switch via dropdown
- Clipboard sync: agent polls local clipboard → sends to viewer; viewer paste → agent sets remote clipboard
- File transfer panel: drag-drop upload to agent, directory browser, download files from remote
- Chat panel: bidirectional text chat forwarded through relay

Agent:
- Multi-monitor capture with set_monitor/set_quality message handlers
- exec_key_combo for Ctrl+Alt+Del and arbitrary combos
- Clipboard polling via pyperclip (both directions)
- File upload/download/list_files with base64 chunked protocol
- Attended mode (--attended): zenity/kdialog/PowerShell consent dialog before accepting stream
- Auto-update: heartbeat checks version, downloads new binary and exec-replaces self (Linux)
- Reports MAC address on registration (for WoL)

Relay:
- Forwards monitor_list, clipboard_content, file_chunk, file_list, chat_message agent→viewer
- Session recording: when RECORDING_DIR env set, saves JPEG frames as .remrec files
- ALLOWED_ORIGINS CORS now set from NEXT_PUBLIC_APP_URL in docker-compose

Database:
- groups table (id, name, description, created_by)
- machines: group_id, mac_address, notes, tags text[]
- Migration 0003 applied

Dashboard:
- Machines page: search, tag filter, group filter, inline notes/tags/rename editing
- MachineCard: inline tag management, group picker, notes textarea
- Admin page: new Groups tab (create/list/delete groups)
- API: PATCH /api/machines/[id] (name, notes, tags, groupId)
- API: GET/POST/DELETE /api/groups
- API: POST /api/machines/wol (broadcast magic packet)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/api/agent/heartbeat/route.ts

@@ -3,9 +3,12 @@ import { machines, sessionCodes } from '@/lib/db/schema'
 import { eq, and, isNotNull, gt } from 'drizzle-orm'
 import { NextRequest, NextResponse } from 'next/server'
 
+// Increment this when a new agent binary is published to /downloads/
+const CURRENT_AGENT_VERSION = '1.0.0'
+
 export async function POST(request: NextRequest) {
   try {
-    const { accessKey } = await request.json()
+    const { accessKey, agentVersion } = await request.json()
 
     if (!accessKey) {
       return NextResponse.json({ error: 'Access key required' }, { status: 400 })
@@ -13,7 +16,7 @@ export async function POST(request: NextRequest) {
 
     const result = await db
       .update(machines)
-      .set({ isOnline: true, lastSeen: new Date() })
+      .set({ isOnline: true, lastSeen: new Date(), agentVersion: agentVersion || undefined })
       .where(eq(machines.accessKey, accessKey))
       .returning({ id: machines.id })
 
@@ -38,11 +41,18 @@ export async function POST(request: NextRequest) {
       .orderBy(sessionCodes.usedAt)
       .limit(1)
 
+    const needsUpdate = agentVersion && agentVersion !== CURRENT_AGENT_VERSION
+    const appUrl = process.env.NEXT_PUBLIC_APP_URL || ''
+    const downloadUrl = needsUpdate
+      ? `${appUrl}/downloads/remotelink-agent-${process.platform === 'win32' ? 'windows.exe' : 'linux'}`
+      : null
+
     return NextResponse.json({
       success: true,
       pendingConnection: pending[0]
         ? { sessionCodeId: pending[0].id, usedBy: pending[0].usedBy }
         : null,
+      updateAvailable: needsUpdate ? { version: CURRENT_AGENT_VERSION, downloadUrl } : null,
     })
   } catch (error) {
     console.error('[Heartbeat] Error:', error)