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>

cypher-executor/src/routes/validate.ts

@@ -0,0 +1,43 @@
+import { Hono } from 'hono';
+import type { Bindings } from '../types';
+import { graphSchema } from '../lib/schemas';
+import { recordTelemetry } from '../lib/telemetry';
+
+export const validateRouter = new Hono<{ Bindings: Bindings }>();
+
+// POST /validate — 驗證圖定義（不執行）
+validateRouter.post('/validate', async (c) => {
+  const start = Date.now();
+  const apiKey = c.req.header('X-Arcrun-API-Key');
+  const userAgent = c.req.header('User-Agent') ?? undefined;
+
+  const body = await c.req.json();
+  const parsed = graphSchema.safeParse(body);
+  if (!parsed.success) {
+    recordTelemetry(c.env, apiKey, {
+      event_type: 'validation_error',
+      error_code: 'schema_failed',
+      duration_ms: Date.now() - start,
+      agent_user_agent: userAgent,
+    }, c.executionCtx);
+    return c.json({ valid: false, errors: parsed.error.issues }, 400);
+  }
+
+  const nodeIds = new Set(parsed.data.nodes.map(n => n.id));
+  const invalidEdges = parsed.data.edges.filter(e => !nodeIds.has(e.from) || !nodeIds.has(e.to));
+
+  if (invalidEdges.length > 0) {
+    recordTelemetry(c.env, apiKey, {
+      event_type: 'validation_error',
+      error_code: 'edge_node_missing',
+      duration_ms: Date.now() - start,
+      agent_user_agent: userAgent,
+    }, c.executionCtx);
+    return c.json({
+      valid: false,
+      errors: invalidEdges.map(e => `邊 ${e.from} → ${e.to} 指向不存在的節點`),
+    }, 400);
+  }
+
+  return c.json({ valid: true, nodeCount: parsed.data.nodes.length, edgeCount: parsed.data.edges.length });
+});