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>

README.md

@@ -56,7 +56,7 @@ Dense reference material lives in [docs/](docs/): [architecture](docs/architectu
 | Desktop    | Electrobun 1.18 (native webview, typed RPC bridge)            |
 | Frontend   | Angular 22 (standalone, signals, zoneless) in `ui/`           |
 | Styling    | Tailwind CSS v4, shadcn-style tokens (no component library)   |
-| Icons      | @ng-icons/mynaui                                              |
+| Icons      | @ng-icons/tdesign-icons                                       |
 | SSH/SFTP   | `ssh2` (pure-JS under Bun)                                    |
 
 The repo is a Bun workspace: the Electrobun app at the root, the Angular app in