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>

client/src/api/client.js

@@ -41,7 +41,11 @@ function safeParse(text) {
 export const api = {
   // ----- auth -----
   me: () => req('/auth/me'),
-  login: (username, password) => req('/auth/login', { method: 'POST', body: { username, password } }),
+  // `extra` carries the honeypot field (and any future login fields).
+  login: (username, password, extra = {}) =>
+    req('/auth/login', { method: 'POST', body: { username, password, ...extra } }),
+  loginTotp: (challenge, code) =>
+    req('/auth/login/totp', { method: 'POST', body: { challenge, code } }),
   logout: () => req('/auth/logout', { method: 'POST' }),
 
   // ----- public -----
@@ -108,6 +112,12 @@ export const api = {
     createUser: (data) => req('/admin/users', { method: 'POST', body: data }),
     updateUser: (id, data) => req(`/admin/users/${id}`, { method: 'PUT', body: data }),
     deleteUser: (id) => req(`/admin/users/${id}`, { method: 'DELETE' }),
+
+    // ----- account security (self-service 2FA) -----
+    getAccount: () => req('/admin/account'),
+    totpSetup: () => req('/admin/account/totp/setup', { method: 'POST' }),
+    totpEnable: (code) => req('/admin/account/totp/enable', { method: 'POST', body: { code } }),
+    totpDisable: (code) => req('/admin/account/totp/disable', { method: 'POST', body: { code } }),
   },
 }