Fix language-search fragment

- mots-clé and language where sharing the same q variable for the input value; they now have unique variables.

The admin language-search-fragment was missing App::boot() which the tag-search
fragment had. This caused the language suggestion dropdown to not return results
in Firefox. Both fragments now follow the same bootstrap pattern.

Rewrote language-search-fragment.php to use the same clean pattern as
tag-search-fragment.php: ->searchLanguages(), simple exact match check,
no predefined exclusion list. Both fragments now share identical structure.

fix: exclude main languages (français, anglais, néerlandais) from language-search suggestions

app/templates/partials/form/language-search.php

@@ -62,7 +62,7 @@ $langCount      = count($selectedLanguages);
         <!-- Search input (hidden when max languages reached) -->
         <div class="tag-search-input-wrap"<?= $langCount >= $maxLanguages ? ' style="display:none"' : '' ?>>
             <input type="text"
-                   name="q"
+                   name="language_search_q"
                    id="<?= htmlspecialchars($id) ?>-search"
                    class="tag-search-input"
                    placeholder="<?= htmlspecialchars($placeholder) ?>"
@@ -188,8 +188,10 @@ $langCount      = count($selectedLanguages);
 
     // Click on suggestion
     dropdown.addEventListener('click', function(e) {
+        console.log('[lang-search] dropdown click, target:', e.target.tagName, e.target.className);
         const btn = e.target.closest('.tag-search-item');
-        if (!btn) return;
+        if (!btn) { console.log('[lang-search] no .tag-search-item found in click path'); return; }
+        console.log('[lang-search] found btn:', btn.getAttribute('data-tag-name'), btn.className);
         selectLang(btn);
     });
 
@@ -224,12 +226,21 @@ $langCount      = count($selectedLanguages);
     search.addEventListener('blur', function() {
         setTimeout(function() {
             if (!dropdown.contains(document.activeElement)) {
+                console.log('[lang-search] blur: hiding dropdown');
                 dropdown.innerHTML = '';
                 selectedIdx = -1;
             }
         }, 150);
     });
 
+    // Log HTMX responses
+    document.body.addEventListener('htmx:afterSwap', function(e) {
+        if (e.detail.target && e.detail.target.id === '<?= htmlspecialchars($id) ?>-suggestions') {
+            console.log('[lang-search] htmx:afterSwap, target:', e.detail.target.id, 'html length:', e.detail.target.innerHTML.length);
+            console.log('[lang-search] innerHTML:', e.detail.target.innerHTML);
+        }
+    });
+
     function htmlEscape(str) {
         const el = document.createElement('span');
         el.textContent = str;

app/templates/partials/form/tag-search.php

@@ -60,7 +60,7 @@ $tagCount    = count($selectedTags);
         <!-- Search input (hidden when max tags reached) -->
         <div class="tag-search-input-wrap"<?= $tagCount >= $maxTags ? ' style="display:none"' : '' ?>>
             <input type="text"
-                   name="q"
+                   name="tag_search_q"
                    id="<?= htmlspecialchars($id) ?>-search"
                    class="tag-search-input"
                    placeholder="<?= htmlspecialchars($placeholder) ?>"