feat(arcrun): implement arcrun MVP — open-source AI workflow engine

Phase 1-5 complete per .agents/specs/u6u-core-mvp/:

**Phase 1 — Cherry-pick & cleanup**
- Create arcrun/ from cypher-executor, credentials, builtins, registry
- Remove 9 InkStone Service Bindings (KBDB, REGISTRY, CLINIC_*, AICEO, MINI_ME)
- Rewrite component-loader: 3-layer (builtin → WASM_BUCKET R2 → error)
- Remove autoPublishMissing.ts, proxy.ts (AICEO), execution-logger.ts (KBDB)
- Clean all KV namespace IDs and InkStone internal URLs from config files

**Phase 2 — contract.yaml completeness**
- Add credentials_required to gmail, google_sheets, telegram, line_notify
- Add config_example to all 21 components with annotated field descriptions

**Phase 3 — Credential injection**
- Add credential-injector.ts: AES-GCM decrypt from CREDENTIALS_KV
- Integrate into GraphExecutor before WASM execution
- Structured errors with repair instructions when credential missing

**Phase 4 — CLI (acr)**
- cli/package.json: arcrun package, bin: acr, deps: commander/js-yaml/chalk/ora
- 8 commands: init, creds push, push, run, validate, parts, list, logs
- Standard mode: writes directly to user's CF KV via CF REST API
- acr init: interactive setup with arcrun.dev API Key registration

**Phase 5 — Open source release prep**
- README.md: 5-minute quickstart, component table, workflow YAML syntax
- CONTRIBUTING.md: TinyGo dev env, component scaffolding, submission flow
- Security audit: no InkStone internal URLs/IDs in committed files
- .gitignore: exclude credentials.yaml, .wrangler, *.wasm

https://claude.ai/code/session_01BnCdSLVH8tUed9VrrPavgT

registry/src/actions/sandboxAcceptance.ts

@@ -0,0 +1,96 @@
+// 沙盒驗收流程：五個步驟依序執行
+// Requirements: 2.1, 2.2, 2.3
+
+import { FORBIDDEN_SYSCALLS } from '../types';
+import type { ComponentContract, SandboxResult, SandboxStep } from '../types';
+
+// ── 步驟 (a)：體積檢查 ────────────────────────────────────────────────────────
+
+function checkSize(wasmBytes: Uint8Array, contract: ComponentContract): string | null {
+  const maxSizeKb = contract.constraints.max_size_kb;
+  const actualKb = wasmBytes.byteLength / 1024;
+  if (actualKb > maxSizeKb) {
+    return `體積 ${actualKb.toFixed(1)}KB 超過上限 ${maxSizeKb}KB`;
+  }
+  return null;
+}
+
+// ── 步驟 (b)：冷啟動時間（Phase 0 mock 0ms）────────────────────────────────────
+
+function checkColdStart(_wasmBytes: Uint8Array, _contract: ComponentContract): string | null {
+  // Phase 0：mock 通過，記錄 0ms
+  // Phase 2 再實作真實測量
+  return null;
+}
+
+// ── 步驟 (c)：syscall 掃描 ────────────────────────────────────────────────────
+
+function scanSyscalls(wasmBytes: Uint8Array): string | null {
+  // 將 .wasm binary 轉為文字，搜尋禁止的 import 字串
+  // WASM binary 中 import section 的函數名稱以 UTF-8 字串形式存在
+  const text = new TextDecoder('utf-8', { fatal: false }).decode(wasmBytes);
+
+  for (const syscall of FORBIDDEN_SYSCALLS) {
+    if (text.includes(syscall)) {
+      return `發現禁止的 syscall：${syscall}`;
+    }
+  }
+  return null;
+}
+
+// ── 步驟 (d)：Gherkin 測試（Phase 0 mock 通過）────────────────────────────────
+
+function runGherkinTests(_wasmBytes: Uint8Array, _contract: ComponentContract): string | null {
+  // Phase 0：mock 通過
+  // Phase 1 再實作真實 Gherkin 執行
+  return null;
+}
+
+// ── 步驟 (e)：runtime 相容測試（Phase 0 mock 通過）────────────────────────────
+
+function checkRuntimeCompat(_wasmBytes: Uint8Array, _contract: ComponentContract): string | null {
+  // Phase 0：mock 通過
+  // Phase 2 再實作真實多 runtime 測試
+  return null;
+}
+
+// ── 主流程 ────────────────────────────────────────────────────────────────────
+
+interface StepDef {
+  name: SandboxStep;
+  run: (wasmBytes: Uint8Array, contract: ComponentContract) => string | null;
+  guideAnchor: string;
+}
+
+const STEPS: StepDef[] = [
+  { name: 'size_check',     run: checkSize,           guideAnchor: '#common-errors' },
+  { name: 'cold_start',     run: checkColdStart,      guideAnchor: '#common-errors' },
+  { name: 'syscall_scan',   run: scanSyscalls,        guideAnchor: '#syscall-constraints' },
+  { name: 'gherkin_tests',  run: runGherkinTests,     guideAnchor: '#local-testing' },
+  { name: 'runtime_compat', run: checkRuntimeCompat,  guideAnchor: '#contract-example' },
+];
+
+export function runSandboxAcceptance(
+  wasmBytes: Uint8Array,
+  contract: ComponentContract,
+): SandboxResult {
+  for (const step of STEPS) {
+    const error = step.run(wasmBytes, contract);
+    if (error !== null) {
+      return {
+        success: false,
+        failed_step: step.name,
+        reason: error,
+        guide_anchor: step.guideAnchor,
+        component_id: contract.canonical_id,
+        version: contract.version,
+      };
+    }
+  }
+
+  return {
+    success: true,
+    component_id: contract.canonical_id,
+    version: contract.version,
+  };
+}