feat: communication spine — gateway, TUI, Discord

Gateway:
- Agent service wrapping Pi SDK createAgentSession (in-process)
- Chat WebSocket gateway (Socket.IO) streaming agent events
- Chat REST controller for synchronous requests
- NestJS module structure: AgentModule (global), ChatModule

CLI:
- Ink-based TUI client connecting to gateway via WebSocket
- Commander-based CLI with `mosaic tui` command
- Streaming message display with React components

Discord:
- Discord.js bot with mention-based activation + DM support
- Routes messages through gateway WebSocket
- Chunked response delivery (2000-char Discord limit)
- Single-guild binding for v0.1.0

Architecture: All channels → Gateway WebSocket → Pi SDK → LLM

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

packages/cli/tsconfig.json

@@ -2,7 +2,8 @@
   "extends": "../../tsconfig.base.json",
   "compilerOptions": {
     "outDir": "dist",
-    "rootDir": "src"
+    "rootDir": "src",
+    "jsx": "react-jsx"
   },
   "include": ["src/**/*"],
   "exclude": ["node_modules", "dist"]