feat(client): adopt the locale seat in theme, sidebar, question, and model

Each package ships its zh/en dictionaries as satisfies-typed pairs (zh is
the key-set source of truth; en is checked complete against it), merges its
namespace into LocaleNamespaceMap, and declares locale: NS at register —
components read the framework-injected typed t seat instead of a
hand-carried inject member. Overlapping verbatim words (retry, submit,
submitting) drop out of package dictionaries in favor of the shared common
vocabulary; the question composer stores validation feedback as dictionary
keys so shown feedback follows a locale switch.

packages/client/ui-question/package.json

@@ -45,6 +45,7 @@
     "react": "^18.2.0"
   },
   "peerDependencies": {
+    "@deepseek-ai/dsh-client-locale": "^0.0.1",
     "@deepseek-ai/dsh-invariants": "^0.0.1",
     "cordis": "^4.0.0-rc.7"
   },