feat(dashboard): add date filter and stat groups components

- Implemented DashboardDateFilter component for selecting date ranges.
- Created DashboardStatGroups component to display various dashboard statistics.
- Added dashboard chart data processing logic to support new chart specifications.
- Introduced reusable Chart components for rendering different types of charts.

Frontend/erp-system/app/globals.css

@@ -81,6 +81,8 @@
   --chart-3: oklch(0.582 0.183 142.495);
   --chart-4: oklch(0.787 0.141 72.031);
   --chart-5: oklch(0.577 0.245 27.325);
+  /* Dashboard charts: one slate ink, tinted lighter for extra series, so every graph matches. */
+  --chart-ink: #5b6b6e;
   --radius: 0.5rem;
   --sidebar: oklch(0.98 0 0);
   --sidebar-foreground: oklch(0.15 0 0);
@@ -120,6 +122,7 @@
   --chart-3: oklch(0.65 0.15 142.495);
   --chart-4: oklch(0.85 0.12 72.031);
   --chart-5: oklch(0.704 0.191 22.216);
+  --chart-ink: #a3b3b6;
   --sidebar: oklch(0.125 0 0);
   --sidebar-foreground: oklch(0.95 0 0);
   --sidebar-primary: oklch(0.645 0.215 16.439);