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/modes/context-usage.test.ts

@@ -6,6 +6,7 @@
  * internals, which massively overcounts.
  */
 import { describe, expect, it } from "bun:test";
+import { type } from "@oh-my-pi/omptype";
 import { arkToWireSchema } from "@oh-my-pi/pi-ai/utils/schema";
 import {
 	type ContextBreakdown,
@@ -14,7 +15,6 @@ import {
 	estimateToolSchemaTokens,
 	renderContextUsage,
 } from "@oh-my-pi/pi-coding-agent/modes/utils/context-usage";
-import { type } from "arktype";
 
 describe("estimateToolSchemaTokens", () => {
 	it("counts arktype tool schemas by their wire JSON Schema, not arktype internals", () => {