fix(typebox): migrate to v1 with extension compat (#3474)

* fix(typebox): migrate to v1 with extension compat

Replace AJV-based validation with TypeBox-native validation, keep legacy extension imports working (including @sinclair/typebox/compiler), and restore coercion for serialized/plain JSON schemas.

This change closes #3112.

* fix(typebox): use canonical imports and harden coercion

Switch first-party code to canonical typebox imports while retaining legacy extension aliases in the loader.

Remove obsolete runtime codegen guards, expand serialized JSON-schema coercion coverage, and update related tests and fixtures.

Fixes #3112.

---------

Co-authored-by: Mario Zechner <badlogicgames@gmail.com>

packages/coding-agent/test/agent-session-concurrent.test.ts

@@ -14,7 +14,7 @@ import {
 	type ImageContent,
 	type TextContent,
 } from "@mariozechner/pi-ai";
-import { Type } from "@sinclair/typebox";
+import { Type } from "typebox";
 import { afterEach, beforeEach, describe, expect, it } from "vitest";
 import { AgentSession } from "../src/core/agent-session.js";
 import { AuthStorage } from "../src/core/auth-storage.js";