fix(redesign): a11y, mobile, perf polish for production push

Comprehensive pre-production sweep across the Aurora redesign — drives
svelte-check to 0 errors / 0 warnings (was 61) without changing visual
intent. Highlights:

- Mobile: hero title shrinks at 480px, signal-list stacks timestamp
  under sentence below 640px, sidebar icon buttons bumped to 40x40
- Light theme: muted-foreground darkened to #3a3560 to clear WCAG AA
  on glass surfaces and the modal close button
- Perf: topbar backdrop-filter 28→14px, mobile-more sheet 28→12px to
  cut concurrent blur layers on mid-tier mobile
- a11y: prefers-reduced-motion mute for aurora drift / pulses /
  shimmer / stagger; aria-label on every icon-only button;
  aria-describedby on Hint; combobox/listbox/aria-activedescendant on
  SearchPalette; modal dialog tabindex; 47 label-without-control
  warnings across 14 form pages cleaned up via for=/id= or label→div
- Dashboard derived state split into topology- vs status-bound layers
  so polling no longer re-runs the full provider/wires computation
- Mobile bottom nav derived from baseNavEntries by key lookup so
  adding a top-level nav entry keeps the two trees in sync
- Bug: template-configs page now respects the global provider filter
  for both the count meter and the type pill (was reading the
  unfiltered cache)
- Misc: portal EventChart tooltip and switch its swatches to Aurora
  tokens; CollapsibleSlot warning state uses warning-fg/-bg tokens
  instead of #d97706; Hint z-index 99999→9999; element refs across
  Modal/EntitySelect/MultiEntitySelect/SearchPalette/IconGridSelect/
  Hint/targets converted to \$state for reactivity; 4 dead
  .topbar-cta selectors removed

frontend/src/routes/command-template-configs/+page.svelte

@@ -400,7 +400,7 @@
 
 		{#if !editing}
 		<div>
-			<label class="block text-sm font-medium mb-1">{t('templateConfig.providerType')}</label>
+			<div class="block text-sm font-medium mb-1">{t('templateConfig.providerType')}</div>
 			<IconGridSelect items={providerTypeItemsFn()} bind:value={form.provider_type} columns={2} />
 		</div>
 		{:else}
@@ -484,7 +484,7 @@
 
 						{#if slotErrors[slot.name]}
 							{#if slotErrorTypes[slot.name] === 'undefined'}
-								<p class="mt-1 text-xs" style="color: #d97706;">⚠ {t('common.undefinedVar')}: {slotErrors[slot.name]}</p>
+								<p class="mt-1 text-xs" style="color: var(--color-warning-fg);">⚠ {t('common.undefinedVar')}: {slotErrors[slot.name]}</p>
 							{:else}
 								<p class="mt-1 text-xs" style="color: var(--color-error-fg);">✕ {t('common.syntaxError')}: {slotErrors[slot.name]}{slotErrorLines[slot.name] ? ` (${t('common.line')} ${slotErrorLines[slot.name]})` : ''}</p>
 							{/if}