[doljak]

What changed

First commit:

• Templates renamed from templates/user/user-*.html.twig to templates/form--user-*.html.twig — correct convention for Drupal to discover them via hook_theme_suggestions_form_alter
• doljak_theme.theme: added hook_theme_suggestions_form_alter and hook_form_alter for all 3 auth forms
• Templates rewritten with correct element.field_name per form — real Drupal User module fields rendered inside the existing static markup
• development.services.yml: Twig debug enabled for local development

Second commit:

• Added missing <form{{ attributes }}> wrapper to all 3 templates — without it the forms rendered correctly but could not submit
• Functional validation complete: login, password reset and registration all tested with invalid and valid data

What to verify

• Login (/user/login): error on invalid credentials, redirect on valid login
• Password reset (/user/password): confirmation message on valid username/email
• Registration (/user/register): account creation with valid data

Closes #86