Refactor text utility classes to Tailwind CSS (#36703)

Replace Fomantic/custom CSS text utility classes with their Tailwind
equivalents:

- `.text.<color>` compound classes → `tw-text-<color>` classes
- `.text.small` (`font-size: 0.75em`) → `tw-text-xs` (11px)
- `.text.truncate` (`overflow-x: hidden; text-overflow: ellipsis;
white-space: nowrap; display: inline-block`) → `tw-inline-block
tw-truncate`

Remove the now-unused CSS rules from `base.css` and `dashboard.css`.

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Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

templates/repo/actions/runs_list.tmpl

@@ -29,7 +29,7 @@
 					{{$errMsg := index $.RunErrors $run.ID}}
 					{{if $errMsg}}
 						<span class="flex-text-inline" data-tooltip-content="{{$errMsg}}">
-							{{svg "octicon-alert" 16 "text red"}}
+							{{svg "octicon-alert" 16 "tw-text-red"}}
 						</span>
 					{{end}}
 				</div>