feat(code): Workers 就緒化（裁定 A）—— singlefile variant + 純 JS SHA-256 prelude

- 沙箱改用 quickjs-emscripten singlefile variant（wasm 內嵌 base64、同步載入），
  CF Workers 相容；sandbox.mjs 成 Node/Worker 共用 runtime-agnostic 核心。
- sha256 curated builtin 改「純 JS SHA-256 prelude 字串注入」，去掉 node:crypto /
  async Web Crypto host-call，Node/Worker 皆決定性（card content_hash 逐字等價）。
- index.ts 成可部署 Worker host（Hono，POST /→runCode），自足不走 TinyGo 模板流程。
- 補 wrangler.toml（arcrun-code / code.arcrun.dev）、tsconfig、DEPLOY.md。
- contract stability 修為 floating（過 registry zod schema 驗證）。
- 單測 12/12 全綠（含 card→envelope 與原模組 planCard 逐欄全等）。

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HJiLCRUU2o3aSpPEzVCt2o

registry/components/code/package-lock.json

@@ -8,6 +8,7 @@
       "name": "arcrun-component-code",
       "version": "0.1.0",
       "dependencies": {
+        "@jitl/quickjs-singlefile-mjs-release-sync": "^0.32.0",
         "quickjs-emscripten": "^0.31.0"
       },
       "devDependencies": {
@@ -462,6 +463,21 @@
       "integrity": "sha512-1yrgvXlmXH2oNj3eFTrkwacGJbmM0crwipA3ohCrjv52gBeDaD7PsTvFYinlAnqU8iPME3LGP437yk05a2oejw==",
       "license": "MIT"
     },
+    "node_modules/@jitl/quickjs-singlefile-mjs-release-sync": {
+      "version": "0.32.0",
+      "resolved": "https://registry.npmjs.org/@jitl/quickjs-singlefile-mjs-release-sync/-/quickjs-singlefile-mjs-release-sync-0.32.0.tgz",
+      "integrity": "sha512-h9g2Dri6WxKNjX6a1+sFAafOVxj1n5YIA1GAzMoSdIqK1M8cG07tz3GxKVC3Gbdutz14uQ3oc3Q2lll8otInhA==",
+      "license": "MIT",
+      "dependencies": {
+        "@jitl/quickjs-ffi-types": "0.32.0"
+      }
+    },
+    "node_modules/@jitl/quickjs-singlefile-mjs-release-sync/node_modules/@jitl/quickjs-ffi-types": {
+      "version": "0.32.0",
+      "resolved": "https://registry.npmjs.org/@jitl/quickjs-ffi-types/-/quickjs-ffi-types-0.32.0.tgz",
+      "integrity": "sha512-v9T+GQpmk43VDJ7d72sf0Nexhk+ArvtUihW27dy7lqAl0zBObFKtSBBIm5RBjwIhE8VwsPPm9PNuvPvNqLWUEg==",
+      "license": "MIT"
+    },
     "node_modules/@jitl/quickjs-wasmfile-debug-asyncify": {
       "version": "0.31.0",
       "resolved": "https://registry.npmjs.org/@jitl/quickjs-wasmfile-debug-asyncify/-/quickjs-wasmfile-debug-asyncify-0.31.0.tgz",