Custom tools with session lifecycle, examples for hooks and tools

- Custom tools: TypeScript modules that extend pi with new tools
  - Custom TUI rendering via renderCall/renderResult
  - User interaction via pi.ui (select, confirm, input, notify)
  - Session lifecycle via onSession callback for state reconstruction
  - Examples: todo.ts, question.ts, hello.ts

- Hook examples: permission-gate, git-checkpoint, protected-paths

- Session lifecycle centralized in AgentSession
  - Works across all modes (interactive, print, RPC)
  - Unified session event for hooks (replaces session_start/session_switch)

- Box component added to pi-tui

- Examples bundled in npm and binary releases

Fixes #190

packages/coding-agent/tsconfig.examples.json

@@ -0,0 +1,14 @@
+{
+	"extends": "../../tsconfig.base.json",
+	"compilerOptions": {
+		"noEmit": true,
+		"baseUrl": ".",
+		"paths": {
+			"@mariozechner/pi-coding-agent": ["./src/index.ts"],
+			"@mariozechner/pi-coding-agent/hooks": ["./src/core/hooks/index.ts"]
+		},
+		"skipLibCheck": true
+	},
+	"include": ["examples/**/*.ts"],
+	"exclude": ["node_modules", "dist"]
+}