feat(auth): auth_static_key WASM primitive + host functions

- wasi-shim gains kv_get / crypto_decrypt / crypto_sign_rs256 host
  functions with strict boundary (ENCRYPTION_KEY never exits Worker).
- registry/components/auth_static_key: TinyGo impl for API-key /
  Bearer / Basic Auth recipes (80% of supported services).
- .component-builds/auth_static_key: independent Worker at
  auth-static-key.arcrun.dev, imports wasi-shim cross-directory.
- cypher-executor/auth-dispatcher routes static_key recipes to the
  new Worker instead of credential-injector TS.

Replaces TS credential injection per
.agents/specs/arcrun/credential-primitives-wasm Phase 1.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

.component-builds/auth_static_key/wrangler.toml

@@ -0,0 +1,23 @@
+name = "arcrun-auth-static-key"
+main = "src/index.ts"
+compatibility_date = "2025-02-19"
+compatibility_flags = ["nodejs_compat"]
+
+[vars]
+COMPONENT_ID = "auth_static_key"
+
+[[routes]]
+pattern = "auth-static-key.arcrun.dev/*"
+zone_name = "arcrun.dev"
+
+# 與 cypher-executor/wrangler.toml 同一組 KV namespace
+[[kv_namespaces]]
+binding = "CREDENTIALS_KV"
+id = "e7f4320f88d343f187e35e3543dd74c9"
+
+[[kv_namespaces]]
+binding = "RECIPES"
+id = "9cf9db905c6241f78503199e58b2ffe0"
+
+# ENCRYPTION_KEY 透過 wrangler secret set 設定
+# wrangler secret put ENCRYPTION_KEY