Add Resource Planning: team capacity, utilisation, workload overview

- Migration 024: adds capacity_hours column to users (default 40h/week)
- /api/resource-planning: aggregates hours from time_entries, open tasks,
  active projects per user with utilisation calculations
- /resource-planning page: overview stats cards, per-member capacity bars
  with colour-coded status (green=available, yellow=busy, orange=near
  capacity, red=overloaded)
- Sidebar: new Resources nav item (BarChart3 icon)

database/migrations/run_all.sql

@@ -88,5 +88,8 @@ BEGIN;
 \echo '=== Running 023_client_portal.sql (Client Portal) ==='
 \i ../../src/app/client-portal/database/020_client_portal.sql
 
+\echo '=== Running 024_resource_planning.sql (Resource Planning) ==='
+\i 024_resource_planning.sql
+
 \echo '=== Migration Complete ==='
 COMMIT;