feat: MUI date-time pickers, multiselect hosts with search, fix host list

- Replace native datetime-local inputs with @mui/x-date-pickers DateTimePicker
  (proper dark-themed calendar popover with time picker, DD/MM/YYYY HH:mm format,
  min/max constraints between pickers, 24h clock)
- Replace single-host Select with Autocomplete (multiple, disableCloseOnSelect):
  checkbox per option, chip display with limitTags=2, built-in search/filter
- getAnalyticsHosts() now unions traffic event hosts WITH all configured proxy host
  domains (parsed from proxyHosts.domains JSON), so every proxy appears in the list
- analytics-db: buildWhere accepts hosts: string[] (empty = all); uses inArray for
  multi-host filtering via drizzle-orm
- All 6 API routes updated: accept hosts param (comma-separated) instead of host

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

.gitignore

@@ -14,3 +14,4 @@ tsconfig.tsbuildinfo
 CLAUDE.local.md
 /caddy-proxy-manager.wiki
 docs/plans
+/.playwright-mcp