feat(caption): let live captions use their own speech model

The speech engine now keeps an auxiliary model next to the dictation model
and transcribes with whichever the request names, reloading it once if the
engine restarted. Settings > STT gains a live-caption model so captions can
run on large-v3-turbo while dictation keeps its own model. The runtime
minimum rises to 1.7.0 because older engines would silently ignore the
model choice.

Suggestion paging moves to Up/Down: the page follows the selection and the
last item waits while more candidates are being generated. The Left/Right
page shortcuts are removed; they did nothing until a page had filled and
clash with Intel's display-rotation hotkeys.

packages/core/src/input-intelligence.ts

@@ -1235,8 +1235,6 @@ export const SUGGESTION_DEFAULTS = {
    * 한 번에 요청하면 느리다(사용자 요청) — 1개씩 순차 요청해 채운다.
    */
   maxCandidatesTotal: 12,
-  /** 오버레이 한 페이지에 보여줄 후보 수. */
-  pageSize: 3,
   maxOutputTokens: 64,
   /** 표시된 제안의 연속 접두가 이만큼 자랐을 때만 재생성한다. */
   regenerateAfterChars: 12,