feat(admin): per-port email/Documenso/branding/reminder settings + invitations

Centralizes everything operators need to configure into the admin panel,
each setting per-port with env fallback.

New admin pages
- /admin              landing page linking to every admin section as a card
- /admin/email        FROM name+address, reply-to, signature/footer HTML,
                      optional SMTP host/port/user/pass override
- /admin/documenso    API URL+key override, EOI Documenso template ID,
                      default EOI pathway (documenso-template vs inapp),
                      "Test connection" button
- /admin/branding     logo URL, primary color, app name, email
                      header/footer HTML
- /admin/reminders    port-level defaults for new interests +
                      port-wide daily-digest delivery window
- /admin/invitations  send / list / resend / revoke CRM invitations

Per-user reminder digest
- /notifications/preferences gains a Reminder digest card:
  immediate / daily / weekly / off, with HH:MM, day-of-week,
  IANA timezone fields. Stored in user_profiles.preferences.reminders.

Plumbing
- port-config.ts typed accessors (getPortEmailConfig, getPortDocumensoConfig,
  getPortBrandingConfig, getPortReminderConfig) — settings → env fallback.
- sendEmail accepts optional portId; resolves From/SMTP from settings
  when supplied.
- documensoFetch + downloadSignedPdf accept optional portId; each public
  function takes it through. checkDocumensoHealth() backs the test button.
- crm-invite.service gains listCrmInvites / revokeCrmInvite / resendCrmInvite
  with audit-log entries (revoke_invite, resend_invite added to AuditAction).
- AdminLandingPage card grid + shared SettingsFormCard component to remove
  per-page form boilerplate.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/app/(dashboard)/[portSlug]/admin/reminders/page.tsx

@@ -0,0 +1,78 @@
+import {
+  SettingsFormCard,
+  type SettingFieldDef,
+} from '@/components/admin/shared/settings-form-card';
+
+const DEFAULT_FIELDS: SettingFieldDef[] = [
+  {
+    key: 'reminder_default_enabled',
+    label: 'Enable reminders by default on new interests',
+    description:
+      'When on, newly-created interests inherit reminderEnabled=true. Users can still toggle it on a per-interest basis.',
+    type: 'boolean',
+    defaultValue: false,
+  },
+  {
+    key: 'reminder_default_days',
+    label: 'Default inactivity days',
+    description:
+      "Default value for an interest's reminderDays field. Reminders fire after this many days of no contact.",
+    type: 'number',
+    placeholder: '7',
+    defaultValue: 7,
+  },
+];
+
+const DIGEST_FIELDS: SettingFieldDef[] = [
+  {
+    key: 'reminder_digest_enabled',
+    label: 'Batch reminders into a daily digest',
+    description:
+      'Off (default): reminders fire as soon as the threshold is hit. On: pending reminders are accumulated and delivered once per day at the digest time.',
+    type: 'boolean',
+    defaultValue: false,
+  },
+  {
+    key: 'reminder_digest_time',
+    label: 'Digest delivery time',
+    description: '24-hour HH:MM in the digest timezone.',
+    type: 'string',
+    placeholder: '09:00',
+    defaultValue: '09:00',
+  },
+  {
+    key: 'reminder_digest_timezone',
+    label: 'Digest timezone',
+    description: 'IANA timezone name used to interpret the delivery time (e.g. Europe/Warsaw).',
+    type: 'string',
+    placeholder: 'Europe/Warsaw',
+    defaultValue: 'Europe/Warsaw',
+  },
+];
+
+export default function ReminderSettingsPage() {
+  return (
+    <div className="space-y-6">
+      <div>
+        <h1 className="text-2xl font-semibold">Reminders</h1>
+        <p className="text-sm text-muted-foreground">
+          Default reminder behaviour for new interests and the optional daily-digest delivery
+          window. Individual users can still configure their own digest preferences in Notifications
+          → Preferences.
+        </p>
+      </div>
+
+      <SettingsFormCard
+        title="Defaults for new interests"
+        description="Applied when an interest is created without an explicit reminder configuration."
+        fields={DEFAULT_FIELDS}
+      />
+
+      <SettingsFormCard
+        title="Daily digest"
+        description="Optional batching window so reminder notifications go out once per day instead of as they fire."
+        fields={DIGEST_FIELDS}
+      />
+    </div>
+  );
+}