Help on every option and every page

- Each option's explanation moves from a line of text under its label to
  a small tooltip on an ⓘ beside it, so forms read calmer and the help is
  still one hover away.
- Help text is ours where written (src/help/texts.ts: domains, people,
  DNS providers, blocked addresses, and the main pages), and the schema's
  description elsewhere.
- A "?" on every list and form opens a side panel: what the page is for,
  what people usually do there, and every option explained.
- Every tooltip and panel carries a stable help id (x:Domain.dnsManagement,
  x:Domain), and manual.ts turns an id into a link to the admin manual
  once one is configured (VITE_MANUAL_URL, or <meta name="manual-url">).
  Until then no link shows.

src/components/common/IconTile.tsx

@@ -46,7 +46,9 @@ export function IconTile({
   const box = size === 'sm' ? 'h-6 w-6 rounded-md' : size === 'lg' ? 'h-10 w-10 rounded-xl' : 'h-7 w-7 rounded-lg';
   const glyph = size === 'sm' ? 'h-3.5 w-3.5' : size === 'lg' ? 'h-5 w-5' : 'h-4 w-4';
   return (
-    <span className={cn('inline-flex shrink-0 items-center justify-center', box, TONE_CLASSES[toneFor(name)], className)}>
+    <span
+      className={cn('inline-flex shrink-0 items-center justify-center', box, TONE_CLASSES[toneFor(name)], className)}
+    >
       {createElement(iconComponent(name), { className: glyph, strokeWidth: 2, 'aria-hidden': true })}
     </span>
   );