chore(vendor): import pi 1.3.0

Imported as a linear vendor commit so forge rebases do not replay the upstream root tree.

git-subtree-dir: third_party/pi

git-subtree-split: 71023aec1546d6d677a65669c5665c0927ce0dd0

third_party/pi/packages/coding-agent/examples/sdk/README.md

@@ -15,18 +15,19 @@ The runtime example shows how to build a recreate function that closes over proc
 | `05-tools.ts` | Built-in tool allowlists |
 | `06-extensions.ts` | Logging, blocking, result modification |
 | `07-context-files.ts` | AGENTS.md context files |
-| `08-slash-commands.ts` | File-based slash commands |
+| `08-prompt-templates.ts` | File-based prompt templates |
 | `09-api-keys-and-oauth.ts` | API key resolution, OAuth config |
 | `10-settings.ts` | Override compaction, retry, terminal settings |
 | `11-sessions.ts` | In-memory, persistent, continue, list sessions |
 | `12-full-control.ts` | Replace everything, no discovery |
 | `13-session-runtime.ts` | Manage runtime-backed session replacement |
+| `14-codemode-mcp.ts` | Add the `codemode`, `tool_search`, and MCP extensions |
 
 ## Running
 
 ```bash
 cd packages/coding-agent
-npx tsx examples/sdk/01-minimal.ts
+node examples/sdk/01-minimal.ts
 ```
 
 ## Quick Reference