Add Bot Activity admin panel: banned-IP view + recent events + emergency unban

Expose the botScore middleware's in-memory scoring/ban state to admins.
Previously state lived only in the store Map with no persistence or API — the
only visibility was tailing container logs.

- botScore: bounded ring buffer (300) recording scan/login-fail/honeypot and
  ban events (most-recent-first); listState() snapshot of all scored IPs;
  unban() to clear a single IP.
- New admin-only endpoints GET /admin/bot-activity and
  POST /admin/bot-activity/unban (RBAC admin gate, IP validated). Unban is
  activity-logged with the admin username.
- Bot Activity tab: currently-banned table with Unban, plus a recent-events
  feed, following the existing admin table patterns.
- Tests for the buffer, listState, and unban (guard lets an unbanned IP back
  through). README updated.

Read + emergency-unban only — no ban-add or weight-editing surface. Buffer is
in-memory, matching the store; not persisted.

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

server/src/router/v1/admin/botActivity.controller.js

@@ -0,0 +1,31 @@
+// Bot-scoring / IP-ban visibility for admins. Read-only view of the botScore
+// middleware's in-memory state plus a recent-events feed, and a single mutating
+// action — an emergency unban for false positives. Mounted behind the admin-only
+// RBAC gate (see admin.routes.js). This is visibility + emergency unban only;
+// there is deliberately no way to add a ban or change scoring weights from here.
+
+const botScore = require('../../../middleware/botScore')
+const activity = require('../../../model/activity/activity.model')
+
+const log = require('../../../utils/logger')('botactivity')
+
+// Current store state (all scored IPs, banned or not) plus the recent-events
+// buffer, most-recent-first. Both are in-memory and reset on process restart.
+async function getBotActivity(req, res) {
+  return res.json({
+    ips: botScore.listState(),
+    events: botScore.recentEvents(),
+  })
+}
+
+// Emergency unban: clear a single IP's entry so it is no longer banned or
+// carrying score. A real administrative action — logged with the admin user.
+async function unbanIp(req, res) {
+  const ip = req.body.ip
+  const removed = botScore.unban(ip)
+  await activity.log({ req, action: 'botscore.unban', detail: { ip, removed } })
+  log.info('IP unbanned by admin', { ip, admin: req.user.username, removed })
+  return res.json({ ip, removed })
+}
+
+module.exports = { getBotActivity, unbanIp }