fix(ui): start with an anti-aliasing the graphics device can't do (#329)

Choosing 8x anti-aliasing in Preferences › Graphics on a device that
only allows 1x and 4x for the window's format made every later start
panic in wgpu's pipeline validation (`Sample count 8 is not supported
by format Bgra8Unorm on this device`), so the app could not be opened
again without editing graphics.json by hand.

- egui-wgpu (vendored): request TEXTURE_ADAPTER_SPECIFIC_FORMAT_FEATURES
  when the adapter has it (WebGPU only guarantees 1x and 4x), and clamp
  the sample count to the largest one the device supports for both the
  colour target and the depth/stencil format. The supported counts are
  exposed as `RenderState::msaa_supported`.
- At start, a saved count the device can't do goes back to the default
  (4x, or the largest supported count below it), is written back, and a
  "Settings were changed" notice says what changed.
- The Anti-aliasing list greys out unsupported counts, `ui.prefs`
  rejects them, and an invalid saved `msaa` loads as the default.
- New messages translated in en, de, ja and ko.

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

crates/ui-egui/src/locales/ko.json

@@ -11,6 +11,11 @@
   "dialog.selected_count": "↖ {count}개 선택됨",
   "document.save_changes": "{name}의 변경 사항을 저장하시겠습니까?",
   "document.unsaved_changes": "{name}에 저장되지 않은 변경 사항이 있습니다. 저장하지 않으면 변경 사항이 사라집니다.",
+  "settings.msaa_applies_on_restart": "안티앨리어싱은 다음에 SolidCraft를 시작할 때 적용됩니다",
+  "settings.msaa_reset": "{setting}: {requested}×는 이 그래픽 장치에서 지원되지 않아 {reset}×로 변경했습니다(지원: {supported}).",
+  "settings.msaa_unsupported": "이 그래픽 장치에서 지원되지 않음",
+  "settings.reset_intro": "다음 설정은 이 컴퓨터에서 작동하지 않아 SolidCraft를 시작할 수 없게 하므로 변경되었습니다:",
+  "settings.reset_title": "설정이 변경되었습니다",
   "sketch.degrees_of_freedom": "자유도 {count}개",
   "sketch.draw_curves": "{linetype} 곡선 그리기",
   "sketch.make_selection": "선택 항목을 {linetype}(으)로 변경",
@@ -27,6 +32,7 @@
   "ui.animate_view_changes": "뷰 변경 애니메이션",
   "ui.animation": "애니메이션",
   "ui.animation_speed": "애니메이션 속도",
+  "ui.anti_aliasing": "안티앨리어싱",
   "ui.apply": "적용",
   "ui.arc": "호",
   "ui.assemble": "조립",
@@ -199,6 +205,7 @@
   "ui.one_side": "한 방향",
   "ui.open": "열기",
   "ui.open_ellipsis": "열기...",
+  "ui.open_preferences": "환경 설정 열기",
   "ui.open_recent": "최근 항목 열기",
   "ui.operation": "작업",
   "ui.options": "옵션",