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/examples/webhook-to-http/workflow.yaml

@@ -0,0 +1,16 @@
+name: webhook_to_http
+description: 收 webhook → 轉發到另一個 HTTP API
+
+flow:
+  - "input >> ON_SUCCESS >> forward"
+
+config:
+  forward:
+    component: http_request
+    url: "https://httpbin.org/post"
+    method: POST
+    headers:
+      Content-Type: "application/json"
+    body_json:
+      received: "{{input}}"
+      timestamp: "{{_now}}"