feat: UI redesign (CSS system, DNS widget, Traefik dashboard widget)

- Replace base.html style block with full CSS design system using custom properties (dark theme, cards, tables, badges, dots, widgets)
- Add DNS blueprint (fablednetmon/dns/) with /dns/ and /dns/rows routes + templates
- Add Traefik /widget route and widget.html fragment for dashboard
- Update dashboard: DNS + Traefik widgets, traefik_enabled config detection
- Update all templates to use new CSS classes (page-title, section-title, card-flush, table, badge-*, dot-*, btn-*)
- Register dns_bp in app.py

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

plugins/traefik/routes.py

@@ -68,3 +68,26 @@ async def index():
             })
 
     return await render_template("traefik/index.html", router_data=router_data)
+
+
+@traefik_bp.get("/widget")
+@require_role(UserRole.viewer)
+async def widget():
+    """HTMX dashboard widget fragment."""
+    async with current_app.db_sessionmaker() as db:
+        result = await db.execute(
+            select(TraefikMetric.router_name).distinct().order_by(TraefikMetric.router_name)
+        )
+        routers = [row[0] for row in result.all()]
+        router_data = []
+        for router in routers:
+            result = await db.execute(
+                select(TraefikMetric)
+                .where(TraefikMetric.router_name == router)
+                .order_by(TraefikMetric.scraped_at.desc())
+                .limit(1)
+            )
+            latest = result.scalar_one_or_none()
+            if latest:
+                router_data.append({"name": router, "latest": latest})
+    return await render_template("traefik/widget.html", router_data=router_data)