feat(ai): add @oh-my-pi/pi-ai package with tool name prefixing

- Port pi-ai from upstream with Bun-first approach (source files, no dist)
- Add cli_ prefix to tool names in OAuth mode to avoid collisions
- Improve beta header handling with proper deduplication
- Convert codex-instructions.md to Bun text embed
- Strip .js extensions from all imports

packages/coding-agent/tsconfig.examples.json

@@ -6,7 +6,7 @@
 			"@oh-my-pi/pi-coding-agent": ["./src/index.ts"],
 			"@oh-my-pi/pi-coding-agent/hooks": ["./src/core/hooks/index.ts"],
 			"@oh-my-pi/pi-tui": ["../tui/src/index.ts"],
-			"@mariozechner/pi-ai": ["../ai/src/index.ts"],
+			"@oh-my-pi/pi-ai": ["../ai/src/index.ts"],
 			"@sinclair/typebox": ["../../node_modules/@sinclair/typebox"]
 		},
 		"skipLibCheck": true