feat(initial): scaffold @push.rocks/smartchat with core, CLI, and web layers

Three-layer architecture built on @push.rocks/smartagent:
- ts/ — ChatSession wrapping runAgent() with conversation state management
- ts_cli/ — ink-based terminal chat TUI (React.createElement, no JSX)
- ts_web/ — Lit web components (smartchat-window, smartchat-message, smartchat-input)

ts_web/index.ts

@@ -0,0 +1,3 @@
+export { SmartchatWindow } from './smartchat-window.js';
+export { SmartchatMessage } from './smartchat-message.js';
+export { SmartchatInput } from './smartchat-input.js';