arcrun — AI workflow execution engine (clean history)

Self-hosted 開源：WASM 零件 + recipe + cypher-executor，跑在你自己的 Cloudflare。

此為重建的乾淨歷史起點（移除曾誤 commit 的 GCP SA 金鑰，舊歷史保留在
richblack/arcrun 與本地 backup 分支）。含：
- acr init --self-hosted installer（建 KV/R2 + codeload 拉預編譯 wasm + wrangler deploy + seed recipe）
- recipe push 把關（資料外流提醒 + 打通檢查）
- 19 個正當零件預編譯 wasm（claude_api/km_writer/kbdb_upsert_block 排除：違反 DECISIONS §1）
- CLI / cypher-executor / registry / 完整 SDD

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

registry/src/routes/validateContract.ts

@@ -0,0 +1,31 @@
+// POST /components/validate-contract
+// Requirements: 1.1, 1.2, 11.5
+
+import { Hono } from 'hono';
+import type { Bindings } from '../types';
+import { validateContract } from '../actions/validateContract';
+
+const app = new Hono<{ Bindings: Bindings }>();
+
+app.post('/', async c => {
+  let body: unknown;
+  try {
+    body = await c.req.json();
+  } catch {
+    return c.json({ valid: false, missing_fields: [], errors: ['request body 必須為合法 JSON'] }, 400);
+  }
+
+  const result = validateContract(body);
+
+  if (result.valid) {
+    return c.json({ valid: true, missing_fields: [], errors: [] }, 200);
+  }
+
+  return c.json({
+    valid: false,
+    missing_fields: result.missing_fields,
+    errors: result.errors,
+  }, 422);
+});
+
+export default app;