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/src/task/types.ts

@@ -1,6 +1,6 @@
+import { type BaseType, type } from "@oh-my-pi/omptype";
 import type { Usage } from "@oh-my-pi/pi-ai";
 import { $env } from "@oh-my-pi/pi-utils";
-import { type BaseType, type } from "arktype";
 import type { AgentSessionEvent } from "../session/agent-session";
 import type { ConfiguredThinkingLevel, TaskEffort } from "../thinking";
 import type { NestedRepoPatch } from "./worktree";