feat(team): add team analytics dashboard

Add a team document-usage dashboard at /t/:teamUrl/analytics for team admins and managers,
behind the NEXT_PUBLIC_FEATURE_TEAM_ANALYTICS_ENABLED rollout flag (enabled by default, set to
"false" to gate it off).

Backend:
- getTeamAnalytics Kysely query over team-produced documents across all folders, with exact
  COUNT(*) (no STATS_COUNT_CAP). Each metric uses its own date axis: Sent/Draft/Pending by
  createdAt, Completed by Envelope.completedAt, Declined by the DOCUMENT_RECIPIENT_REJECTED
  audit-log timestamp.
- resolveAnalyticsPeriod turns calendar presets into half-open [start, end) ranges in the
  viewer's timezone, falling back to UTC.
- team.getAnalytics tRPC route gated to ADMIN/MANAGER.

Frontend:
- Standalone /t/:teamUrl/analytics route whose loader gates the flag and role, silently
  redirecting members to documents.
- Headline metrics and compact stat tiles, a member multiselect filter, a calendar-preset
  period selector, and an empty state.
- Role- and flag-gated nav entries in the desktop and mobile navigation.

Tests:
- Unit tests for the period resolver (timezone and preset boundaries).
- Integration/E2E tests for the query semantics (date axes, audit-log decline, all-folders
  aggregation, sender attribution), access control, filters and the empty state.

apps/remix/app/components/general/app-nav-desktop.tsx

@@ -1,5 +1,7 @@
 import { useSession } from '@documenso/lib/client-only/providers/session';
+import { IS_TEAM_ANALYTICS_ENABLED } from '@documenso/lib/constants/app';
 import { isPersonalLayout } from '@documenso/lib/utils/organisations';
+import { canExecuteTeamAction } from '@documenso/lib/utils/teams';
 import { cn } from '@documenso/ui/lib/utils';
 import { Button } from '@documenso/ui/primitives/button';
 import { msg } from '@lingui/core/macro';
@@ -45,7 +47,7 @@ export const AppNavDesktop = ({ className, setIsCommandMenuOpen, ...props }: App
       return [];
     }
 
-    return [
+    const links = [
       {
         href: `/t/${teamUrl}/documents`,
         label: msg`Documents`,
@@ -55,6 +57,19 @@ export const AppNavDesktop = ({ className, setIsCommandMenuOpen, ...props }: App
         label: msg`Templates`,
       },
     ];
+
+    if (
+      currentTeam &&
+      IS_TEAM_ANALYTICS_ENABLED() &&
+      canExecuteTeamAction('MANAGE_TEAM', currentTeam.currentTeamRole)
+    ) {
+      links.push({
+        href: `/t/${currentTeam.url}/analytics`,
+        label: msg`Analytics`,
+      });
+    }
+
+    return links;
   }, [currentTeam, organisations]);
 
   return (