fix(arcrun): address PR #2 review findings

Security:
- init.ts: remove cf_api_token from POST /register (only email sent to arcrun.dev)
- cf-api.ts: remove base64 fallback in encryptCredential, throw clear error if key missing

Correctness:
- submitComponent.ts: replace KBDB dependency with SUBMISSIONS_KV + R2 (standalone)
- registry/types.ts: remove KBDB_URL/KBDB_INTERNAL_TOKEN, add SUBMISSIONS_KV/ANALYTICS_KV
- webhooks.ts: add waitUntil(writeExecutionVerdict) for fire-and-forget analytics
- execution-logger.ts: create missing module (was imported but didn't exist)
- cypher-executor/types.ts + wrangler.toml: add ANALYTICS_KV binding
- gmail/telegram/google_sheets/line_notify/http_request: no_network_syscall false (api category)
- init.ts: replace require() with await import() for ES module compatibility

Cleanup:
- Remove arcrun/builtins/ (dead code — initComponents used old HTTP endpoint model,
  all 21 components now in TinyGo WASM under registry/components/)

Docs:
- tasks.md: update to reflect completed work and remaining items

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

builtins/package-lock.json

@@ -1,49 +0,0 @@
-{
-  "name": "@inkstone/u6u-builtins-worker",
-  "version": "1.0.0",
-  "lockfileVersion": 3,
-  "requires": true,
-  "packages": {
-    "": {
-      "name": "@inkstone/u6u-builtins-worker",
-      "version": "1.0.0",
-      "dependencies": {
-        "hono": "^4.7.0"
-      },
-      "devDependencies": {
-        "@cloudflare/workers-types": "^4.20250219.0",
-        "typescript": "^5.7.0"
-      }
-    },
-    "node_modules/@cloudflare/workers-types": {
-      "version": "4.20260329.1",
-      "resolved": "https://registry.npmjs.org/@cloudflare/workers-types/-/workers-types-4.20260329.1.tgz",
-      "integrity": "sha512-LxBHrYYI/AZ6OCbUzRqRgg6Rt1qev2KxN2NNd3saye41AO2g52cYvHV+ohts5oPnrIUD7YRjbgN/J3NU7e7m5A==",
-      "dev": true,
-      "license": "MIT OR Apache-2.0"
-    },
-    "node_modules/hono": {
-      "version": "4.12.9",
-      "resolved": "https://registry.npmjs.org/hono/-/hono-4.12.9.tgz",
-      "integrity": "sha512-wy3T8Zm2bsEvxKZM5w21VdHDDcwVS1yUFFY6i8UobSsKfFceT7TOwhbhfKsDyx7tYQlmRM5FLpIuYvNFyjctiA==",
-      "license": "MIT",
-      "engines": {
-        "node": ">=16.9.0"
-      }
-    },
-    "node_modules/typescript": {
-      "version": "5.9.3",
-      "resolved": "https://registry.npmjs.org/typescript/-/typescript-5.9.3.tgz",
-      "integrity": "sha512-jl1vZzPDinLr9eUt3J/t7V6FgNEw9QjvBPdysz9KfQDD41fQrC2Y4vKQdiaUpFT4bXlb1RHhLpp8wtm6M5TgSw==",
-      "dev": true,
-      "license": "Apache-2.0",
-      "bin": {
-        "tsc": "bin/tsc",
-        "tsserver": "bin/tsserver"
-      },
-      "engines": {
-        "node": ">=14.17"
-      }
-    }
-  }
-}