Replaced boolean `smtp_use_tls` with explicit `smtp_security` enum field supporting "none", "starttls", and "ssl" modes. Added database migration to create `smtp_security` column with "starttls" default. Updated mailer to use SMTP_SSL client for direct SSL connections on port 465 and SMTP with STARTTLS for port 587. Modified admin settings UI to show dropdown selector with encryption options and auto-adjust
Implemented comprehensive email invitation functionality for new users. Added SMTP settings management in admin panel with configuration UI for host, port, credentials, sender details, and TLS options. Created invite token system with 48-hour expiration and single-use enforcement. Added mailer module with HTML email templates in German theme styling (radial gradient backgrounds, gold accents, bordered cards). Implemented invite