Merge branch 'stack/agent-profiles-5-web-ui' into stack/agent-profiles-8-authoring

The composer's preset seat stays removed here — this layer moved it to the
hero chip and the session-header action — so only the model seat takes the
`modelSeatLocked` narrowing master introduced.

Conflicts:
	apps/web/tests/snapshots/*/*.expected.md
	packages/client/connection/README.md
	packages/client/connection/README.zh.md
	packages/client/ui-conversation/src/client/skeleton/InputBar.tsx
	packages/host/apiproxy/src/fetch/client.ts

apps/cli/package.json

@@ -68,6 +68,7 @@
     "@deepseek-ai/dsh-frontend-static": "workspace:^",
     "@deepseek-ai/dsh-host-apiproxy": "workspace:^",
     "@deepseek-ai/dsh-host-webserver": "workspace:^",
+    "@deepseek-ai/dsh-llm-mock-server": "workspace:^",
     "@deepseek-ai/dsh-loader-smoke": "workspace:^",
     "@deepseek-ai/dsh-settings": "workspace:^",
     "@deepseek-ai/dsh-system-prompt": "workspace:^",