feat(tui): add terminal user interface with Ink

Add a full TUI for Claudeman using Ink (React for CLI):
- StartScreen: Shows existing sessions from screens.json
- TabBar: Session tabs with status indicators
- TerminalView: PTY output display with scrolling
- StatusBar: Session info and keyboard shortcuts
- HelpOverlay: Full keyboard shortcut reference

Features:
- Session discovery from ~/.claudeman/screens.json
- Tab navigation (Ctrl+Tab, Ctrl+1-9)
- Create new sessions (connects to web API)
- Kill sessions via screen commands
- Keyboard-driven navigation

Usage: claudeman tui

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

package.json

@@ -38,11 +38,16 @@
     "chalk": "^5.3.0",
     "commander": "^12.1.0",
     "fastify": "^5.1.0",
+    "ink": "^6.6.0",
+    "ink-spinner": "^5.0.0",
+    "ink-text-input": "^6.0.0",
     "node-pty": "^1.1.0",
+    "react": "^19.2.3",
     "uuid": "^10.0.0"
   },
   "devDependencies": {
     "@types/node": "^20.14.0",
+    "@types/react": "^19.2.9",
     "@types/uuid": "^10.0.0",
     "@vitest/coverage-v8": "^4.0.17",
     "agent-browser": "^0.6.0",