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/help/manual.ts

@@ -0,0 +1,39 @@
+/*
+ * SPDX-FileCopyrightText: 2026 Coffey Labs
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+/**
+ * Links from in-app help to the INBUXA admin manual (MkDocs). Every tooltip
+ * and help panel carries a stable id, `x:Domain.dnsManagement` for a field
+ * or `x:Domain` for a page, and this is the one place that turns an id into
+ * an address. Until a manual is published there is no base URL and no link
+ * is shown.
+ *
+ * The base URL comes from VITE_MANUAL_URL at build time, or from
+ * <meta name="manual-url" content="https://…"> at deploy time.
+ */
+function manualBase(): string | null {
+  const fromMeta =
+    typeof document !== 'undefined' ? document.querySelector('meta[name="manual-url"]')?.getAttribute('content') : null;
+  const base = (fromMeta || (import.meta.env.VITE_MANUAL_URL as string | undefined) || '').trim();
+  return base ? base.replace(/\/+$/, '') : null;
+}
+
+/**
+ * The manual page for a help id: `x:Domain.dnsManagement` becomes
+ * `<base>/reference/domain/#dnsmanagement`, `x:Domain` becomes
+ * `<base>/reference/domain/`. The manual's page names must follow this.
+ */
+export function manualUrl(id: string): string | null {
+  const base = manualBase();
+  if (!base) return null;
+  const [object, field] = id.split('.', 2);
+  const page = object
+    .replace(/^x:/, '')
+    .replace(/\//g, '-')
+    .replace(/([a-z0-9])([A-Z])/g, '$1-$2')
+    .toLowerCase();
+  return `${base}/reference/${page}/${field ? `#${field.toLowerCase()}` : ''}`;
+}