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/middleware/botScore.js

@@ -72,6 +72,28 @@ const PATH_WEIGHTS = [
 // ip -> { score, lastSeen, bannedUntil }
 const store = new Map()
 
+// ── Recent-events ring buffer ────────────────────────────────────────────────
+// A bounded, most-recent-first log of notable events (scanner hit, ban, honeypot,
+// login failure) so admins can see recent activity without tailing container
+// logs. In-memory only, matching the store — not persisted. Oldest entries fall
+// off once EVENT_CAP is reached. Each event: { ts, ip, type, path, points,
+// score, reason }.
+const EVENT_CAP = 300
+const events = []
+
+function recordEvent(evt) {
+  events.push(evt)
+  if (events.length > EVENT_CAP) events.shift()
+}
+
+// Most-recent-first slice of the event buffer (default: whole buffer, capped).
+function recentEvents(limit = EVENT_CAP) {
+  const n = Math.min(limit, events.length)
+  const out = new Array(n)
+  for (let i = 0; i < n; i++) out[i] = events[events.length - 1 - i]
+  return out
+}
+
 // Return the scanner weight for a request path (0 if it is a legitimate path).
 function scoreForPath(pathname) {
   const p = String(pathname || '').toLowerCase()
@@ -97,7 +119,10 @@ function isBanned(ip, now = Date.now()) {
 
 // Add points to an IP's score. Applies quiet-period decay first, then bans the
 // IP if the new score crosses the threshold. Returns the updated entry.
-function addScore(ip, points, now = Date.now(), reason = 'scan') {
+//
+// `path` is the request path when the points came from a scanned URL (else null),
+// recorded into the event buffer alongside the resulting score.
+function addScore(ip, points, now = Date.now(), reason = 'scan', path = null) {
   const e = getEntry(ip)
   // Decay: if the IP has been quiet longer than QUIET_MS (and is not currently
   // banned), forget its accumulated score before adding the new hit.
@@ -106,10 +131,17 @@ function addScore(ip, points, now = Date.now(), reason = 'scan') {
   }
   e.score += points
   e.lastSeen = now
-  if (e.score >= BAN_THRESHOLD && e.bannedUntil <= now) {
+  const justBanned = e.score >= BAN_THRESHOLD && e.bannedUntil <= now
+  if (justBanned) {
     e.bannedUntil = now + BAN_MS
     log.warn('IP banned', { ip, score: e.score, reason, banMs: BAN_MS })
   }
+  // Record the scoring event, then a distinct ban event if this hit crossed the
+  // threshold — so the feed shows both "why" (the hit) and the resulting ban.
+  recordEvent({ ts: now, ip, type: reason, path, points, score: e.score, reason })
+  if (justBanned) {
+    recordEvent({ ts: now, ip, type: 'ban', path, points: 0, score: e.score, reason })
+  }
   return e
 }
 
@@ -136,7 +168,7 @@ function guard(req, res, next) {
   // if the IP is reused), but the 404 does not depend on it.
   const points = scoreForPath(req.path)
   if (points > 0) {
-    const e = addScore(ip, points, now, 'scan')
+    const e = addScore(ip, points, now, 'scan', req.path)
     log.warn('scanner path hit', { ip, path: req.path, points, score: e.score })
     return notFound(res)
   }
@@ -197,9 +229,34 @@ function stopSweeper() {
 // Start sweeping on load — this is a single long-lived process.
 startSweeper()
 
+// Snapshot of every IP currently in the store, for the admin view: score, ban
+// state, when the ban lifts, and last-seen. Most-recently-seen first.
+function listState(now = Date.now()) {
+  const out = []
+  for (const [ip, e] of store) {
+    out.push({
+      ip,
+      score: e.score,
+      banned: e.bannedUntil > now,
+      bannedUntil: e.bannedUntil || 0,
+      lastSeen: e.lastSeen || 0,
+    })
+  }
+  out.sort((a, b) => b.lastSeen - a.lastSeen)
+  return out
+}
+
+// Manually clear a single IP's entry (admin emergency unban / false positive).
+// Fully removes it from the store, so it is neither banned nor carrying score.
+// Returns true if an entry existed and was removed.
+function unban(ip) {
+  return store.delete(ip)
+}
+
 // Test/ops helpers.
 function _reset() {
   store.clear()
+  events.length = 0
 }
 function _snapshot(ip) {
   const e = store.get(ip)
@@ -213,6 +270,9 @@ module.exports = {
   isBanned,
   recordLoginFailure,
   recordHoneypot,
+  recentEvents,
+  listState,
+  unban,
   sweep,
   startSweeper,
   stopSweeper,