feat: add master password hint functionality

- Updated user model to include masterPasswordHint.
- Modified sync handler to return masterPasswordHint.
- Implemented password hint retrieval in public API.
- Enhanced user profile management to allow updating of password hint.
- Added UI components for displaying and editing password hint.
- Updated localization files for new password hint strings.
- Improved rate limiting for sensitive public requests.
- Adjusted database schema to accommodate master password hint.

webapp/src/components/AppGlobalOverlays.tsx

@@ -8,6 +8,9 @@ export interface AppConfirmState {
   message: string;
   danger?: boolean;
   showIcon?: boolean;
+  confirmText?: string;
+  cancelText?: string;
+  hideCancel?: boolean;
   onConfirm: () => void;
 }
 
@@ -40,6 +43,9 @@ export default function AppGlobalOverlays(props: AppGlobalOverlaysProps) {
         message={props.confirm?.message || ''}
         danger={props.confirm?.danger}
         showIcon={props.confirm?.showIcon}
+        confirmText={props.confirm?.confirmText}
+        cancelText={props.confirm?.cancelText}
+        hideCancel={props.confirm?.hideCancel}
         onConfirm={() => props.confirm?.onConfirm()}
         onCancel={props.onCancelConfirm}
       />

webapp/src/components/AppMainRoutes.tsx

@@ -77,6 +77,7 @@ export interface AppMainRoutesProps {
   uploadingSendFileName: string;
   sendUploadPercent: number | null;
   onChangePassword: (currentPassword: string, nextPassword: string, nextPassword2: string) => Promise<void>;
+  onSavePasswordHint: (masterPasswordHint: string) => Promise<void>;
   onEnableTotp: (secret: string, token: string) => Promise<void>;
   onOpenDisableTotp: () => void;
   onGetRecoveryCode: (masterPassword: string) => Promise<string>;
@@ -198,6 +199,7 @@ export default function AppMainRoutes(props: AppMainRoutesProps) {
                 profile={props.profile}
                 totpEnabled={props.totpEnabled}
                 onChangePassword={props.onChangePassword}
+                onSavePasswordHint={props.onSavePasswordHint}
                 onEnableTotp={props.onEnableTotp}
                 onOpenDisableTotp={props.onOpenDisableTotp}
                 onGetRecoveryCode={props.onGetRecoveryCode}

webapp/src/components/AuthViews.tsx

@@ -13,6 +13,7 @@ interface RegisterValues {
   email: string;
   password: string;
   password2: string;
+  passwordHint: string;
   inviteCode: string;
 }
 
@@ -24,6 +25,7 @@ interface AuthViewsProps {
   registerValues: RegisterValues;
   unlockPassword: string;
   emailForLock: string;
+  loginHintLoading: boolean;
   onChangeLogin: (next: LoginValues) => void;
   onChangeRegister: (next: RegisterValues) => void;
   onChangeUnlock: (password: string) => void;
@@ -33,6 +35,8 @@ interface AuthViewsProps {
   onGotoLogin: () => void;
   onGotoRegister: () => void;
   onLogout: () => void;
+  onTogglePasswordHint: () => void;
+  onShowLockedPasswordHint: () => void;
 }
 
 function PasswordField(props: {
@@ -87,6 +91,17 @@ export default function AuthViews(props: AuthViewsProps) {
               autoComplete="current-password"
               onInput={props.onChangeUnlock}
             />
+            <div className="auth-support-row">
+              <span />
+              <button
+                type="button"
+                className="auth-link-btn"
+                onClick={props.onShowLockedPasswordHint}
+                disabled={unlockBusy}
+              >
+                {t('txt_show_password_hint')}
+              </button>
+            </div>
             <button type="submit" className="btn btn-primary full" disabled={unlockBusy || !props.unlockReady}>
               <Unlock size={16} className="btn-icon" />
               {unlockBusy ? t('txt_unlocking') : t('txt_unlock')}
@@ -147,6 +162,18 @@ export default function AuthViews(props: AuthViewsProps) {
               autoComplete="new-password"
               onInput={(v) => props.onChangeRegister({ ...props.registerValues, password2: v })}
             />
+            <label className="field">
+              <span>{t('txt_password_hint_optional')}</span>
+              <input
+                className="input"
+                maxLength={120}
+                value={props.registerValues.passwordHint}
+                placeholder={t('txt_password_hint_register_placeholder')}
+                onInput={(e) =>
+                  props.onChangeRegister({ ...props.registerValues, passwordHint: (e.currentTarget as HTMLInputElement).value })
+                }
+              />
+            </label>
             <label className="field">
               <span>{t('txt_invite_code_optional')}</span>
               <input
@@ -199,6 +226,19 @@ export default function AuthViews(props: AuthViewsProps) {
             onInput={(v) => props.onChangeLogin({ ...props.loginValues, password: v })}
             autoFocus
           />
+          <div className="auth-support-row">
+            <span />
+            <button
+              type="button"
+              className="auth-link-btn"
+              onClick={props.onTogglePasswordHint}
+              disabled={loginBusy || !props.loginValues.email.trim()}
+            >
+              {props.loginHintLoading
+                ? t('txt_loading_password_hint')
+                : t('txt_show_password_hint')}
+            </button>
+          </div>
           <button type="submit" className="btn btn-primary full" disabled={loginBusy}>
             <LogIn size={16} className="btn-icon" />
             {loginBusy ? t('txt_logging_in') : t('txt_log_in')}

webapp/src/components/ConfirmDialog.tsx

@@ -10,6 +10,7 @@ interface ConfirmDialogProps {
   confirmText?: string;
   cancelText?: string;
   danger?: boolean;
+  hideCancel?: boolean;
   onConfirm: () => void;
   onCancel: () => void;
   children?: ComponentChildren;
@@ -37,10 +38,12 @@ export default function ConfirmDialog(props: ConfirmDialogProps) {
           <Check size={14} className="btn-icon" />
           {props.confirmText || t('txt_yes')}
         </button>
-        <button type="button" className="btn btn-secondary dialog-btn" onClick={props.onCancel}>
-          <X size={14} className="btn-icon" />
-          {props.cancelText || t('txt_no')}
-        </button>
+        {!props.hideCancel && (
+          <button type="button" className="btn btn-secondary dialog-btn" onClick={props.onCancel}>
+            <X size={14} className="btn-icon" />
+            {props.cancelText || t('txt_no')}
+          </button>
+        )}
         {props.afterActions}
       </form>
     </div>

webapp/src/components/SettingsPage.tsx

@@ -9,6 +9,7 @@ interface SettingsPageProps {
   profile: Profile;
   totpEnabled: boolean;
   onChangePassword: (currentPassword: string, nextPassword: string, nextPassword2: string) => Promise<void>;
+  onSavePasswordHint: (masterPasswordHint: string) => Promise<void>;
   onEnableTotp: (secret: string, token: string) => Promise<void>;
   onOpenDisableTotp: () => void;
   onGetRecoveryCode: (masterPassword: string) => Promise<string>;
@@ -40,6 +41,7 @@ export default function SettingsPage(props: SettingsPageProps) {
   const [currentPassword, setCurrentPassword] = useState('');
   const [newPassword, setNewPassword] = useState('');
   const [newPassword2, setNewPassword2] = useState('');
+  const [passwordHint, setPasswordHint] = useState(props.profile.masterPasswordHint || '');
   const [secret, setSecret] = useState(() => localStorage.getItem(totpSecretStorageKey) || randomBase32Secret(32));
   const [token, setToken] = useState('');
   const [totpLocked, setTotpLocked] = useState(props.totpEnabled);
@@ -54,6 +56,10 @@ export default function SettingsPage(props: SettingsPageProps) {
     setTotpLocked(true);
   }, [props.totpEnabled]);
 
+  useEffect(() => {
+    setPasswordHint(props.profile.masterPasswordHint || '');
+  }, [props.profile.masterPasswordHint]);
+
   const qrDataUrl = useMemo(() => {
     const qr = qrcode(0, 'M');
     qr.addData(buildOtpUri(props.profile.email, secret));
@@ -81,6 +87,28 @@ export default function SettingsPage(props: SettingsPageProps) {
 
   return (
     <div className="stack">
+      <section className="card">
+        <h3>{t('txt_profile')}</h3>
+        <label className="field">
+          <span>{t('txt_password_hint_optional')}</span>
+          <input
+            className="input"
+            maxLength={120}
+            value={passwordHint}
+            placeholder={t('txt_password_hint_placeholder')}
+            onInput={(e) => setPasswordHint((e.currentTarget as HTMLInputElement).value)}
+          />
+          <div className="field-help">{t('txt_password_hint_register_help')}</div>
+        </label>
+        <button
+          type="button"
+          className="btn btn-secondary"
+          onClick={() => void props.onSavePasswordHint(passwordHint)}
+        >
+          {t('txt_save_profile')}
+        </button>
+      </section>
+
       <section className="card">
         <h3>{t('txt_change_master_password')}</h3>
         <label className="field">