feat: introduced omptype validation package and migrated workspace dependencies

- Introduce `@oh-my-pi/omptype` as a new ArkType-compatible schema validation package featuring a lazy JIT runtime, JSON Schema emission, and compatibility adapters.
- Replace `arktype` across workspace packages and test utilities with `@oh-my-pi/omptype`.
- Add benchmark suites, tests, and documentation for the new validation engine and adapters.
- Update workspace build, test runner, and release configurations to include the new package.

packages/coding-agent/test/agent-session-eager-compaction.test.ts

@@ -1,5 +1,6 @@
 import { afterEach, beforeEach, describe, expect, it, vi } from "bun:test";
 import * as path from "node:path";
+import { type } from "@oh-my-pi/omptype";
 import { Agent, type AgentMessage, type AgentTool } from "@oh-my-pi/pi-agent-core";
 import * as compactionModule from "@oh-my-pi/pi-agent-core/compaction";
 import type { Model, TextContent } from "@oh-my-pi/pi-ai";
@@ -14,7 +15,6 @@ import { convertToLlm } from "@oh-my-pi/pi-coding-agent/session/messages";
 import { SessionManager } from "@oh-my-pi/pi-coding-agent/session/session-manager";
 import { TodoTool, type ToolSession, USER_TODO_EDIT_CUSTOM_TYPE } from "@oh-my-pi/pi-coding-agent/tools";
 import { TempDir } from "@oh-my-pi/pi-utils";
-import { type } from "arktype";
 
 // Re-injecting eager preludes after compaction: the first-message preludes are the
 // oldest messages, so compaction summarizes them away and the agent silently loses