refactor(api): converge the Remote failure vocabulary and client surface

Single RemoteError with a merge-extensible, domain-prefixed code map;
owners throw at the failure point; streams surface marked failures;
clients consume ctx.remote directly with isRemoteFailure as the only
discrimination point and construct no failure instances.

packages/api/session-controller/package.json

@@ -99,6 +99,7 @@
     "@deepseek-ai/dsh-skill": "workspace:^",
     "@deepseek-ai/dsh-session-title": "workspace:^",
     "@deepseek-ai/dsh-subagent": "workspace:^",
+    "@deepseek-ai/dsh-util-time": "workspace:^",
     "@deepseek-ai/dsh-typert-protocol": "workspace:^",
     "@deepseek-ai/dsh-typert-registry": "workspace:^",
     "@deepseek-ai/dsh-workspace": "workspace:^",
@@ -137,6 +138,7 @@
     "@deepseek-ai/dsh-storage-domain": "workspace:^",
     "@deepseek-ai/dsh-storage-json": "workspace:^",
     "@deepseek-ai/dsh-subagent": "workspace:^",
+    "@deepseek-ai/dsh-util-time": "workspace:^",
     "@deepseek-ai/dsh-typert-protocol": "workspace:^",
     "@deepseek-ai/dsh-typert-registry": "workspace:^",
     "@deepseek-ai/dsh-util-crypto": "workspace:^",