Initial monorepo setup with npm workspaces and dual TypeScript configuration

- Set up npm workspaces for three packages: pi-tui, pi-agent, and pi (pods)
- Implemented dual TypeScript configuration:
  - Root tsconfig.json with path mappings for development and type checking
  - Package-specific tsconfig.build.json for clean production builds
- Configured lockstep versioning with sync script for inter-package dependencies
- Added comprehensive documentation for development and publishing workflows
- All packages at version 0.5.0 ready for npm publishing

packages/agent/src/index.ts

@@ -0,0 +1,15 @@
+// Main exports for pi-agent package
+
+export type { AgentConfig, AgentEvent, AgentEventReceiver } from "./agent.js";
+export { Agent } from "./agent.js";
+export type { ArgDef, ArgDefs, ParsedArgs } from "./args.js";
+// CLI utilities
+export { parseArgs, printHelp } from "./args.js";
+// CLI main function
+export { main } from "./cli.js";
+// Renderers
+export { ConsoleRenderer } from "./renderers/console-renderer.js";
+export { JsonRenderer } from "./renderers/json-renderer.js";
+export { TuiRenderer } from "./renderers/tui-renderer.js";
+export type { SessionData, SessionEvent, SessionHeader } from "./session-manager.js";
+export { SessionManager } from "./session-manager.js";