feat: add analytics dashboard with traffic monitoring

- Parse Caddy access logs every 30s into traffic_events SQLite table
- GeoIP country lookup via maxmind (GeoLite2-Country.mmdb)
- 90-day retention with automatic purge
- Analytics page with interval (24h/7d/30d) and per-host filtering:
  - Stats cards: total requests, unique IPs, blocked count, block rate
  - Requests-over-time area chart (ApexCharts)
  - SVG world choropleth map (d3-geo + topojson-client, React 19 compatible)
  - Top countries table with flag emojis
  - HTTP protocol donut chart
  - Top user agents horizontal bar chart
  - Recent blocked requests table with pagination
- Traffic (24h) summary card on Overview page linking to analytics
- 7 authenticated API routes under /api/analytics/
- Share caddy-logs volume with web container (read-only)
- group_add caddy GID to web container for log file read access

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

app/api/analytics/hosts/route.ts

@@ -0,0 +1,9 @@
+import { NextResponse } from 'next/server';
+import { requireUser } from '@/src/lib/auth';
+import { getAnalyticsHosts } from '@/src/lib/analytics-db';
+
+export async function GET() {
+  await requireUser();
+  const hosts = await getAnalyticsHosts();
+  return NextResponse.json(hosts);
+}