Feature: Implement secure public pre-registration flow with CAPTCHA and HTMX dashboard

- Created V16 Flyway migration for pre_inscription and token_pre_inscription tables.
- Added PreInscription and TokenPreInscription entities with respective repositories.
- Updated SecurityConfig to allow public access to /inscription-public/**.
- Implemented CaptchaValidationService to interact with Cloudflare Turnstile API.
- Created PublicInscriptionController for managing the QR code entry, CAPTCHA validation, ephemeral tokens, and public form submission.
- Added public Thymeleaf views (demarrer, formulaire, succes, lien-expire) with TailwindCSS.
- Developed AdminPreInscriptionController and PreInscriptionService to handle back-office validation and rejection workflows.
- Built the admin pre-inscriptions dashboard list view.
- Added a dynamic, polling notification badge in the sidebar using HTMX, auto-updating on validation/rejection events.

as-talange-web/src/main/java/com/astalange/web/config/SecurityConfig.java

@@ -25,7 +25,7 @@ public class SecurityConfig {
     public SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception {
         http
             .authorizeHttpRequests(auth -> auth
-                .requestMatchers("/css/**", "/js/**", "/images/**").permitAll()
+                .requestMatchers("/css/**", "/js/**", "/images/**", "/inscription-public/**").permitAll()
                 .requestMatchers("/change-password").authenticated()
                 .requestMatchers("/utilisateurs/**", "/saisons/**", "/categories/**", "/equipes/**", "/modespaiement/**", "/equipements/**").hasRole("ADMIN")
                 .requestMatchers("/paiements/**", "/paiement/**").hasAnyRole("ADMIN", "TRESORERIE")