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/layout/TopBar.tsx

@@ -137,7 +137,11 @@ export function TopBar() {
         {/* INBUXA: the three areas, one click away, where the eye already looks. */}
         {schema && navigableLayouts.length > 1 && (
           <TooltipProvider delayDuration={150}>
-            <div className="hidden items-center gap-0.5 rounded-xl bg-muted p-1 sm:flex" role="tablist" aria-label={t('sections', 'Sections')}>
+            <div
+              className="hidden items-center gap-0.5 rounded-xl bg-muted p-1 sm:flex"
+              role="tablist"
+              aria-label={t('sections', 'Sections')}
+            >
               {navigableLayouts.map((layout) => {
                 const isActive = layout.name === activeSection;
                 return (