Harden admin login: RBAC-safe controls, 2FA, bot-scoring, rate limits (#9)

Adds a layered set of protections around the admin login and the app edge.

Trust proxy (server/src/utils/trustProxy.js)
- Configurable via TRUST_PROXY; pin to the newt agent ("ptero") LAN IP so
  X-Forwarded-For is trusted ONLY from that peer. A blanket "true" is
  rejected (coerced to 1) to prevent XFF spoofing that would dodge every
  IP-based control. DEBUG_TRUST_PROXY logs peer/XFF/req.ip to re-verify the
  proxy IP without a redeploy. Documents the Omada static-reservation
  assumption.

Login throttling (server/src/middleware/loginProtection.js, rateLimit.js)
- express-slow-down progressive delay + the existing hard rate cap + a
  separate per-IP exponential backoff that persists across the rate window.
  All failures return one generic message (no user/pass disclosure).

Honeypot (login form + auth.controller)
- Hidden, plausibly-named field ("company"); a filled value fails
  generically and is scored as an unambiguous bot.

Optional per-user TOTP 2FA (speakeasy/qrcode)
- totp_secret/totp_enabled columns (+ idempotent migration). Self-service
  Account page: enroll via QR, confirm a code to enable, code-gated disable.
- Login is two-step for enrolled users: after the password, a short-lived
  signed challenge (stage:'totp', not a session) is required before the
  real session is issued.

Bot / scanner scoring + IP ban (server/src/middleware/botScore.js)
- Weighted CMS-scanner paths (this app uses none). Junk paths 404 FIRST,
  unconditionally — independent of score/ban state, so a scanner rotating
  through fresh Cloudflare IPs gets no free pass. /wp-admin/install.php is
  the top-weighted near-1-hit ban (worst offender in prod logs). Per-IP
  score with quiet-period decay temp-bans an IP from ALL routes once past a
  (deliberately low) threshold, to protect /admin from credential stuffing.
  Failed logins and honeypot hits feed the same score.
- Periodic sweep evicts stale, unbanned, quiet entries so the in-memory
  store can't grow unbounded; the interval is unref'd and cleared on
  graceful shutdown.

Tests: node --test suite (40) covering trust-proxy parsing + live req.ip
(incl. pinned-IP), rate limiter + exponential backoff, honeypot rejection,
TOTP verify (enabled/disabled) + challenge-isn't-a-session, bot-score
threshold/decay/ban + junk-404-independence + install.php + store sweep.

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

server/src/utils/auth.js

@@ -7,6 +7,8 @@ const users = require('../model/users/users.model')
 const JWT_SECRET = process.env.JWT_SECRET
 const JWT_EXPIRES_IN = process.env.JWT_EXPIRES_IN || '1d'
 const COOKIE_NAME = process.env.COOKIE_NAME || 'uomm_token'
+// Lifetime of the short-lived "password verified, awaiting TOTP" token.
+const TOTP_CHALLENGE_TTL = process.env.TOTP_CHALLENGE_TTL || '5m'
 
 if (!JWT_SECRET) {
   log.warn('JWT_SECRET is not set — set it in .env before going to production')
@@ -25,6 +27,19 @@ function verifyToken(token) {
   }
 }
 
+// Short-lived token issued after the password step for users with TOTP enabled.
+// It is NOT a session: it carries stage:'totp' so getUserFromRequest rejects it,
+// and it is only accepted by verifyTotpChallenge to gate the second factor.
+function signTotpChallenge(user) {
+  return jwt.sign({ id: user.id, stage: 'totp' }, JWT_SECRET, { expiresIn: TOTP_CHALLENGE_TTL })
+}
+
+function verifyTotpChallenge(token) {
+  const decoded = verifyToken(token)
+  if (!decoded || decoded.stage !== 'totp') return null
+  return decoded
+}
+
 // Rough max-age (ms) for the cookie, parsed from JWT_EXPIRES_IN (e.g. 1d, 12h, 30m).
 function cookieMaxAge() {
   const m = /^(\d+)([dhms])$/.exec(String(JWT_EXPIRES_IN).trim())
@@ -71,11 +86,15 @@ function extractToken(req) {
   return null
 }
 
-// Returns the decoded user or null without rejecting the request.
+// Returns the decoded user or null without rejecting the request. Stage-tagged
+// tokens (e.g. the TOTP challenge) are explicitly NOT sessions, so an attacker
+// can't present a half-authenticated challenge token as a full login.
 function getUserFromRequest(req) {
   const token = extractToken(req)
   if (!token) return null
-  return verifyToken(token)
+  const decoded = verifyToken(token)
+  if (!decoded || decoded.stage) return null
+  return decoded
 }
 
 // Gate middleware for protected (admin) routes. Re-validates the token against
@@ -110,6 +129,8 @@ module.exports = {
   COOKIE_NAME,
   signToken,
   verifyToken,
+  signTotpChallenge,
+  verifyTotpChallenge,
   setAuthCookie,
   clearAuthCookie,
   getUserFromRequest,