fix(hud): AI summary in the UI language, canonical feed state, partial aggregation

The HUD sends its locale with the summary context; the proxy names that
language in the instructions and the input, English when missing or
unsupported. The model returns {summary, feedState}; the HUD shows the
summary only when feedState matches its own state for a view that is not
nominal, and appends its own translated state tag.

partial joins the shared feed-state table between fallback and nominal,
so one partial layer no longer reads off and partial plus nominal no
longer reads nominal.

scripts/package-boundaries.json

@@ -336,6 +336,7 @@
     "exports": ["./server/providers/openai"],
     "modules": [
       "src/i18n/marker.js",
+      "src/i18n/locale.js",
       "src/hudLayoutPolicy.js",
       "server/providers/common/rate-limit.js",
       "server/providers/common/request.js",