fix(hud): keep English out of localized summaries, cap ja/zh by characters only

Second follow-up review fixes:

- Japanese and Chinese summaries are capped at 20 characters only, without
  the five-token cut first, and the cap steps back to a space instead of
  splitting a Latin word.
- The HUD request sends localized layer names in feedProvenance too and
  leaves the English narration note out outside English. A non-English reply
  that still echoes a feed-state id or a translated English layer name falls
  back to the deterministic line.
- A camera move during typing shows the deterministic line, not a fragment.
- A view with no place labels and no enabled layer does not ask the model.
- Behaviour tests on IntelHUD replace the regex checks of hud.js; docs and
  the instruction wording updated.

docs/CURRENT-STATE.md

@@ -5255,10 +5255,10 @@ and unreachable upstream (502/504) separately from road geometry.
 ### AI HUD Summary (June 2026)
 
 - HUD `SUMMARY` readout requests a five-word intelligence-style summary from `/api/openai/hud-summary` (model `OPENAI_HUD_SUMMARY_MODEL`, default `gpt-5-nano`, minimal reasoning).
-- Input is the live basemap label context (place/street/nearby-place labels + enabled layers, the layer names as the user sees them) and `feedProvenance`; the model is instructed not to infer from coordinates.
+- Input is the live basemap label context (place/street/nearby-place labels + enabled layers) and `feedProvenance`, with every layer name as the user sees it; outside English the narration note is left out, since a small model copies its English words. The model is instructed not to infer from coordinates. A view with no labels and no enabled layer is not sent: the deterministic line is shown.
 - Language (October 2026): the HUD sends `locale`, which is part of the dedupe signature. The proxy keeps a shipped locale (English otherwise) and names the language in the instructions and at the start of the input; Japanese and Chinese get a 20-character phrase instead of five words.
-- The reply is structured (`text.format` JSON schema): `{summary, feedState}`, `feedState` being the snapshot state or `none`. For a view that is not nominal, a missing or different `feedState` falls back to the deterministic line. An accepted summary and the deterministic line carry the HUD's own translated state: the state word leads and the layer names trail (`STALE | … | LIVE FLIGHTS`), so the one-line readout clips neither the warning nor the text. `get_hud_caption` builds its caption the same way and returns `feedState`.
-- Output is sanitized to five words (20 characters when the request locale is Japanese or Chinese, whatever script the words use); falls back to the deterministic telemetry summary on error/timeout (5s abort); typewriter animation on update.
+- The reply is structured (`text.format` JSON schema): `{summary, feedState}`, `feedState` being the snapshot state or `none`. For a view that is not nominal, a missing or different `feedState` falls back to the deterministic line. An accepted summary and the deterministic line carry the HUD's own translated state: the state word leads and the layer names trail (`STALE | … | LIVE FLIGHTS`), so the one-line readout never clips the warning; the text and then the layer names may be cut off on narrow layouts. Outside English a reply that echoes a feed-state id or an English layer name the UI translates falls back too. `get_hud_caption` builds its caption the same way and returns `feedState`.
+- Output is sanitized to five words, or for a Japanese or Chinese request locale to 20 characters (stepping back to a space rather than splitting a Latin word); falls back to the deterministic telemetry summary on error/timeout (5s abort); typewriter animation on update; a camera move during typing shows the deterministic line instead of the fragment.
 - `partial` is a feed state of its own, ranked between `fallback` and `nominal`, so one partial layer no longer reads as off and partial plus nominal reads partial (HUD, voice view state, `analyst_query`, `brief`, the agent world packet). Its narration note says coverage is incomplete rather than not live.
 - A summary asked for before the camera starts moving never paints over the next view: `moveStart` marks the summary dirty and bumps its revision, as `moveEnd` does, aborts the request in flight and stops a reply still typing; neither a reply nor a fallback line (on an error, the 5 s timeout, the abort, or a failed context build) paints once the revision has moved. A dropped request forgets its signature and a timeout counts as a failure, so the next 15 s tick asks again even over the same place. An interrupted typewriter reply also forgets its signature; fully displayed answers remain reusable.