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/user/settings/keys_principal.tmpl

@@ -17,7 +17,7 @@
 			{{range .Principals}}
 				<div class="flex-item">
 					<div class="flex-item-leading">
-						<span class="text {{if .HasRecentActivity}}green{{end}}" {{if .HasRecentActivity}}data-tooltip-content="{{ctx.Locale.Tr "settings.principal_state_desc"}}"{{end}}>{{svg "octicon-key" 32}}</span>
+						<span class="{{if .HasRecentActivity}}tw-text-green{{end}}" {{if .HasRecentActivity}}data-tooltip-content="{{ctx.Locale.Tr "settings.principal_state_desc"}}"{{end}}>{{svg "octicon-key" 32}}</span>
 					</div>
 					<div class="flex-item-main">
 						<div class="flex-item-title">{{.Name}}</div>