PHP dynamique + cache JSON, nettoyage CSS/HTML, CI Forgejo

- Renommage classes/IDs (BEM cohérent, anglais, noms sémantiques)
- Correction HTML : h3→h2 FAQ, button>a→a[role=button] CTA mobile
- Conversion index.html → index.php (FR/EN) avec cache JSON depuis API Kirby
- Pages merci/thanks converties en PHP dynamique
- Ajout includes/cache.php + includes/config.php (cache TTL 5min)
- Ajout CI Forgejo (deploy FTP via lftp)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

assets/js/donation.js

@@ -74,7 +74,7 @@
 
   function initTabs() {
     const tabButtons = document.querySelectorAll('.nav--tabs__btn');
-    const containers = document.querySelectorAll('.btn--donation__container');
+    const containers = document.querySelectorAll('.donation-grid');
 
     tabButtons.forEach((button, index) => {
       button.addEventListener('click', () => {
@@ -91,9 +91,9 @@
 
   function initDonationButtons() {
     const oneOffContainer = document.querySelector(
-      '[data-donnation="one-off"]'
+      '[data-donation="one-off"]'
     );
-    const oneOffButtons = oneOffContainer.querySelectorAll('.btn--donation');
+    const oneOffButtons = oneOffContainer.querySelectorAll('.donation-btn');
 
     oneOffButtons.forEach((button, index) => {
       if (index < AMOUNTS.oneOff.length) {
@@ -118,9 +118,9 @@
     });
 
     const monthlyContainer = document.querySelector(
-      '[data-donnation="monthly"]'
+      '[data-donation="monthly"]'
     );
-    const monthlyButtons = monthlyContainer.querySelectorAll('.btn--donation');
+    const monthlyButtons = monthlyContainer.querySelectorAll('.donation-btn');
 
     monthlyButtons.forEach((button, index) => {
       if (index < AMOUNTS.monthly.length) {