feat(desktop): honest, unified dictation popups with Esc to cancel

Wave 3 of the 2026-09-28 design overhaul.

- Esc (no modifiers) cancels an in-progress dictation, recording or
  processing: VoiceModeService.requestEscape() queues the dead 'escape'
  action. Clicking the capsule cancels only while recording, so a stray
  click during processing no longer throws the text away.
- Errors show in the user's language: bootstrap now passes error.code to
  the tip (the translated branch never ran), and one core classifier
  (voice-error-message) feeds both the tip and the main-window alert.
- Capsule: bars stay flat without input (no fake "alive" wobble before the
  mic opens), an indeterminate bar replaces the made-up percentage, the
  partial transcript stays visible while processing, an Esc hint, and a
  brief "Inserted" state so success is visible.
- All six popups share popups/_shared (Pretendard, one panel radius,
  selection, kbd hints, reduced motion). History/command popups get
  titles, listbox roles and window sizes from popup-list-geometry (empty
  states were clipped); the command popup's "0" key is registered;
  result popup explains why it appeared and can be closed; captions keep
  a theme-independent dark backing on purpose.
- Popup themes follow the OS when set to system and the document lang
  follows the app language.
- Site hero demo mirrors the new capsule (done state, indeterminate bar,
  Esc hint; 10 locales).

site/src/i18n/index.ts

@@ -81,6 +81,10 @@ export interface Translations {
     docLine: string
     /** 캡슐의 처리 중 문구 */
     processing: string
+    /** 캡슐 완료 표시 — 앱 recording-tip 의 done 상태 */
+    inserted: string
+    /** 캡슐 오른쪽 키 안내 */
+    cancelHint: string
     stateIdle: string
     stateListening: string
     statePolishing: string