feat(admin): add GET /api/admin/logs for ring buffer + rate_limit_events

app/api/admin/logs/route.ts

@@ -0,0 +1,34 @@
+import { NextResponse } from 'next/server'
+import { isAdminAuthenticated } from '@/lib/admin/session'
+import { log } from '@/lib/observability/logger'
+import { listRateLimitEvents } from '@/lib/db/analytics'
+import type { LogLevel } from '@/lib/observability/types'
+
+export const dynamic = 'force-dynamic'
+
+const VALID_LEVELS: LogLevel[] = ['debug', 'info', 'warn', 'error']
+
+export async function GET(request: Request) {
+  if (!(await isAdminAuthenticated())) {
+    return NextResponse.json({ code: 'UNAUTHORIZED' }, { status: 401 })
+  }
+
+  const url = new URL(request.url)
+  const view = url.searchParams.get('view') ?? 'logs'
+  const limit = Math.min(500, Number(url.searchParams.get('limit') ?? '100'))
+  const sinceRaw = url.searchParams.get('since')
+  const since = sinceRaw ? Number(sinceRaw) : undefined
+
+  if (view === 'rate_limit') {
+    const rows = listRateLimitEvents({ limit, since })
+    return NextResponse.json({ view, rows })
+  }
+
+  const levelParam = url.searchParams.get('level')
+  const level = levelParam && (VALID_LEVELS as string[]).includes(levelParam)
+    ? (levelParam as LogLevel)
+    : undefined
+
+  const events = log.recent({ level, limit, since })
+  return NextResponse.json({ view: 'logs', rows: events })
+}