feat(hub): reCAPTCHA v2 on Register and Password Reset pages

Server-side verification module, CaptchaConfig in hub.toml,
captcha_site_key exposed via /v1/hub/info, useCaptcha() hook
in the SPA with stable DOM rendering (strength bar always present
to avoid Preact re-ordering the captcha widget). Native clients
(auth_key path) skip captcha. All 10 locales updated.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

1 files changed, 95 insertions, 16 deletions

diff --git a/packages/meshbay-hub/src/meshbay_hub/static/auth-page.js b/packages/meshbay-hub/src/meshbay_hub/static/auth-page.js
index 7c92d52..df08bc4 100644
--- a/packages/meshbay-hub/src/meshbay_hub/static/auth-page.js
+++ b/packages/meshbay-hub/src/meshbay_hub/static/auth-page.js
@@ -1,5 +1,5 @@
 import {
-  html, useState,
+  html, useState, useEffect, useRef, useCallback,
 } from './vendor/htm-preact.js';
 import { t } from './i18n.js';
 import {
@@ -10,6 +10,75 @@ import * as platform from './platform.js';
 const PASSWORD_MIN_BITS = 60;
 const PASSWORD_MIN_LEN = 12;
 
+// ── reCAPTCHA v2 helper ──────────────────────────────────────────────────────
+
+let _captchaSiteKey = null;
+let _captchaKeyFetched = false;
+
+async function fetchCaptchaSiteKey() {
+  if (_captchaKeyFetched) return _captchaSiteKey;
+  try {
+    const info = await hubFetch('/v1/hub/info');
+    _captchaSiteKey = info.captcha_site_key || null;
+  } catch { _captchaSiteKey = null; }
+  _captchaKeyFetched = true;
+  return _captchaSiteKey;
+}
+
+function loadRecaptchaScript() {
+  if (document.getElementById('recaptcha-script')) return;
+  const s = document.createElement('script');
+  s.id = 'recaptcha-script';
+  s.src = 'https://www.google.com/recaptcha/api.js?render=explicit';
+  s.async = true;
+  s.defer = true;
+  document.head.appendChild(s);
+}
+
+function useCaptcha() {
+  const [siteKey, setSiteKey] = useState(_captchaSiteKey);
+  const [token, setToken] = useState(null);
+  const containerRef = useRef(null);
+  const widgetId = useRef(null);
+
+  useEffect(() => {
+    fetchCaptchaSiteKey().then(k => {
+      if (k) { setSiteKey(k); loadRecaptchaScript(); }
+    });
+  }, []);
+
+  useEffect(() => {
+    if (!siteKey || !containerRef.current) return;
+    const poll = setInterval(() => {
+      if (window.grecaptcha && window.grecaptcha.render && widgetId.current === null) {
+        clearInterval(poll);
+        widgetId.current = window.grecaptcha.render(containerRef.current, {
+          sitekey: siteKey,
+          callback: (tk) => setToken(tk),
+          'expired-callback': () => setToken(null),
+          theme: document.documentElement.getAttribute('data-theme') === 'dark'
+            ? 'dark' : 'light',
+        });
+      }
+    }, 100);
+    return () => clearInterval(poll);
+  }, [siteKey]);
+
+  const reset = useCallback(() => {
+    if (widgetId.current !== null && window.grecaptcha) {
+      window.grecaptcha.reset(widgetId.current);
+      setToken(null);
+    }
+  }, []);
+
+  const widget = siteKey
+    ? html`<div ref=${containerRef}
+                style="display:flex;justify-content:center;margin:12px 0"></div>`
+    : null;
+
+  return { token, widget, reset, enabled: !!siteKey };
+}
+
 function passwordBits(pw) {
   if (!pw) return 0;
   let pool = 0;
@@ -142,6 +211,7 @@ export function RegisterPage() {
   const [recoverySaved, setRecoverySaved] = useState(false);
   const [recoveryCopied, setRecoveryCopied] = useState(false);
   const [emailRecovery, setEmailRecovery] = useState(true);
+  const captcha = useCaptcha();
 
   const onSubmit = async (e) => {
     e.preventDefault();
@@ -177,7 +247,11 @@ export function RegisterPage() {
       } else {
         await hubFetch('/v1/users/register', {
           method: 'POST',
-          body: { username: name, email, password, pk_user_ed25519: '', pk_user_x25519: '' },
+          body: {
+            username: name, email, password,
+            pk_user_ed25519: '', pk_user_x25519: '',
+            captcha_token: captcha.token,
+          },
         });
         setPhase('verify');
       }
@@ -322,18 +396,16 @@ export function RegisterPage() {
           <input type="password" placeholder="${t('register.password')}" value=${password}
                  onInput=${e => setPassword(e.target.value)}
                  autocomplete="new-password" required minlength="8" />
-          ${password && html`
-            <div style="margin:-4px 0 10px">
-              <div style="height:4px;background:var(--border);border-radius:2px;overflow:hidden">
-                <div style=${`height:100%;width:${Math.min(100, passwordBits(password) / 100 * 100)}%;
-                     background:${passwordBits(password) < PASSWORD_MIN_BITS ? 'var(--error)'
-                       : passwordBits(password) < 80 ? 'var(--yellow, #f59e0b)' : 'var(--success)'}`}></div>
-              </div>
-              <p style="font-size:0.8em;color:var(--text-dim);margin-top:4px">
-                ${t('register.strength', { bits: passwordBits(password) })}
-              </p>
+          <div style=${`margin:-4px 0 10px;${password ? '' : 'visibility:hidden;height:0;margin:0;overflow:hidden'}`}>
+            <div style="height:4px;background:var(--border);border-radius:2px;overflow:hidden">
+              <div style=${`height:100%;width:${Math.min(100, passwordBits(password) / 100 * 100)}%;
+                   background:${passwordBits(password) < PASSWORD_MIN_BITS ? 'var(--error)'
+                     : passwordBits(password) < 80 ? 'var(--yellow, #f59e0b)' : 'var(--success)'}`}></div>
             </div>
-          `}
+            <p style="font-size:0.8em;color:var(--text-dim);margin-top:4px">
+              ${t('register.strength', { bits: passwordBits(password) })}
+            </p>
+          </div>
           <input type="password" placeholder="${t('register.confirm')}" value=${confirm}
                  onInput=${e => setConfirm(e.target.value)}
                  autocomplete="new-password" required />
@@ -343,8 +415,9 @@ export function RegisterPage() {
                    onChange=${e => setEmailRecovery(e.target.checked)} />
             <span>${t('register.recovery_email_opt')}</span>
           </label>
+          ${captcha.widget}
           ${error && html`<div class="error-msg">${error}</div>`}
-          <button type="submit" disabled=${loading}>
+          <button type="submit" disabled=${loading || (captcha.enabled && !captcha.token)}>
             ${loading ? t('register.loading') : t('register.submit')}
           </button>
         </form>
@@ -375,6 +448,7 @@ export function ResetPasswordPage({ onLogin }) {
   const [busy, setBusy] = useState(false);
   const [progress, setProgress] = useState(null);
   const [result, setResult] = useState(null);
+  const captcha = useCaptcha();
 
   const requestCode = async (e) => {
     e.preventDefault();
@@ -384,7 +458,10 @@ export function ResetPasswordPage({ onLogin }) {
     try {
       await hubFetch('/v1/users/password/reset-request', {
         method: 'POST',
-        body: { username: username.trim(), email: email.trim() },
+        body: {
+          username: username.trim(), email: email.trim(),
+          captcha_token: captcha.token,
+        },
       });
       setPhase('form');
     } catch (err) {
@@ -493,8 +570,10 @@ export function ResetPasswordPage({ onLogin }) {
           <input type="email" placeholder="${t('register.email')}" value=${email}
                  onInput=${e => setEmail(e.target.value)}
                  autocomplete="email" required />
+          ${captcha.widget}
           ${error && html`<div class="error-msg">${error}</div>`}
-          <button type="submit" disabled=${busy}>${t('reset.send_code')}</button>
+          <button type="submit" disabled=${busy || (captcha.enabled && !captcha.token)}>
+            ${t('reset.send_code')}</button>
         </form>`}
 
       ${phase === 'form' && html`