test(client): migrate the ui-conversation and web benches onto SlotTestRuntime

The five ui-conversation machinery specs (apply-inject, chat-apply,
chat-toolview-slot, service-orchestration, selection-survival — now .tsx)
and the web app/app-shell specs assemble through the runtime instead of
hand-built Context + SlotsService + fake-session scaffolding per suite.
Session behavior mocks are typed against ISession, so incomplete fakes
fail at compile time.

packages/client/web/package.json

@@ -31,6 +31,7 @@
   "devDependencies": {
     "@cordisjs/plugin-loader": "workspace:^",
     "@deepseek-ai/dsh-client-runtime": "workspace:^",
+    "@deepseek-ai/dsh-client-test-runtime": "workspace:^",
     "@deepseek-ai/dsh-invariants": "workspace:^",
     "@types/react": "~18.3.1",
     "@types/react-dom": "~18.3.0",