fix(api): repair runtime closure, gateway client bundle, and $host coverage

- python/sdk-runtime: add @deepseek-ai/dsh-util-time so the runtime
  dependency closure stays closed (dsh-subagent now depends on it).
- api/gateway: drop the dsh.client.external request for
  dsh-typert-protocol and admit the protocol package into INLINE_SAFE
  instead. The loader module table has no supplier for the protocol
  package, so the built client factory threw at require time; the
  protocol layer is duplication-safe by design (string marker,
  code-based discrimination), which is the inline-safe admission
  criterion.
- api/gateway tests: cover the $host getter (live service read,
  pre-ready home, and the construction-time fallback after the
  Connection service is withdrawn).

python/sdk-runtime/package.json

@@ -119,6 +119,7 @@
     "@deepseek-ai/dsh-user-approval": "workspace:^",
     "@deepseek-ai/dsh-anonymous-user-id": "workspace:^",
     "@deepseek-ai/dsh-user-questions": "workspace:^",
+    "@deepseek-ai/dsh-util-time": "workspace:^",
     "@deepseek-ai/dsh-web": "workspace:^",
     "@deepseek-ai/dsh-web-fetch-http": "workspace:^",
     "@deepseek-ai/dsh-web-search-deepseek": "workspace:^",