fix: Align workers dropdown to right edge so it stays on screen

Changed dropdown-menu positioning from left:0 to right:0 so the
dropdown expands leftward instead of rightward, keeping it visible
within the viewport.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

ui/src/app/components/miner-switcher/miner-switcher.component.ts

@@ -185,7 +185,6 @@ import { MinerService } from '../../miner.service';
     .dropdown-menu {
       position: absolute;
       top: calc(100% + 4px);
-      left: 0;
       right: 0;
       min-width: 260px;
       background: var(--color-surface-100);