feat: add dashboards — tables, CRUD API, widget data endpoint

- New dashboards table (name, description, layout, is_default)
- New dashboard_widgets table (view_id, title, widget_type, position, config)
- GET/POST/PATCH/DELETE /dashboards
- GET/POST/PATCH/DELETE /dashboards/:id/widgets
- GET /dashboards/:id/widgets/:id/data — runs saved view filters,
  returns pre-aggregated data for count/ticket_list/status_chart/grouped_counts
- is_default uniqueness enforced on PATCH

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

web/src/components/widgets/grouped-counts-widget.tsx

@@ -0,0 +1,39 @@
+"use client";
+
+import type { WidgetData } from "@/lib/types";
+
+export function GroupedCountsWidget({ data }: { data: WidgetData }) {
+  const groups = data.groups ?? {};
+  const entries = Object.entries(groups).sort(([, a], [, b]) => b - a);
+  const max = entries.length > 0 ? Math.max(...entries.map(([, c]) => c)) : 1;
+
+  if (entries.length === 0) {
+    return (
+      <div className="flex h-full items-center justify-center rounded-lg border border-border bg-card p-4">
+        <p className="text-xs text-muted-foreground">No data</p>
+      </div>
+    );
+  }
+
+  return (
+    <div className="flex h-full flex-col overflow-hidden rounded-lg border border-border bg-card">
+      <div className="border-b border-border px-3 py-2">
+        <span className="text-xs font-semibold text-foreground">{data.title}</span>
+      </div>
+      <div className="flex-1 space-y-1.5 overflow-auto p-3">
+        {entries.map(([label, count]) => (
+          <div key={label} className="flex items-center gap-2 text-xs">
+            <span className="w-20 shrink-0 truncate text-foreground">{label}</span>
+            <div className="flex-1">
+              <div
+                className="h-2.5 rounded-sm bg-primary/60 transition-all"
+                style={{ width: `${Math.round((count / max) * 100)}%` }}
+              />
+            </div>
+            <span className="w-8 shrink-0 text-right tabular-nums text-muted-foreground">{count}</span>
+          </div>
+        ))}
+      </div>
+    </div>
+  );
+}