Switch the UI icons from mynaui to TDesign

Swap @ng-icons/mynaui for @ng-icons/tdesign-icons (34.0.0, the release
matching @ng-icons/core), drawn at TDesign's native stroke. Each former
mynaui name maps to one TDesign name everywhere it was used; the unused
ArrowLeftRight is dropped. The options button's ellipsis goes from 1.5rem
to 0.8rem: TDesign's dots span 18 of 24 units against mynaui's 8, so this
keeps today's footprint.

Co-Authored-By: Claude <noreply@anthropic.com>

ui/package.json

@@ -14,7 +14,7 @@
     "@angular/core": "^22.0.0",
     "@angular/platform-browser": "^22.0.0",
     "@ng-icons/core": "^34.0.0",
-    "@ng-icons/mynaui": "^34.0.0",
+    "@ng-icons/tdesign-icons": "^34.0.0",
     "rxjs": "~7.8.0",
     "tslib": "^2.3.0"
   },