Method createModalContainer

chat/components/ShareModals.js:393–426

* Create modal container with backdrop

(className = '')

        // Prevent main input from stealing focus while modal is open
        const mainInput = document.getElementById('message-input');
        if (mainInput) {
            mainInput.setAttribute('tabindex', '-1');
            this._restoreMainInput = () => mainInput.removeAttribute('tabindex');
        }

        // Focus trap: keep focus within modal
        modal.addEventListener('keydown', (e) => {
            if (e.key === 'Tab') {
                const focusable = modal.querySelectorAll('button, input, select, textarea, [tabindex]:not([tabindex="-1"])');
                if (focusable.length === 0) return;

                const first = focusable[0];
                const last = focusable[focusable.length - 1];

                if (e.shiftKey && document.activeElement === first) {
                    e.preventDefault();
                    last.focus();
                } else if (!e.shiftKey && document.activeElement === last) {
                    e.preventDefault();
                    first.focus();
                }
            }
        });

        return modal;
    }

    /**
     * Setup password toggle functionality (uses CSS masking since type="text" to avoid password managers)
     */
    setupPasswordToggle(container) {
        const toggleBtn = container.querySelector('.toggle-password-btn');
        const passwordInput = container.querySelector('.password-input');
        if (!toggleBtn || !passwordInput) return;

        // Prevent button from stealing focus