fix: HTTP fallback for clipboard — execCommand('copy') textarea method

- Added copyToClipboard() in utils.js with dual strategy:
  - HTTPS: navigator.clipboard.writeText() (modern API)
  - HTTP: textarea + execCommand('copy') (legacy fallback)
- viewer.js: uses copyToClipboard() instead of direct navigator.clipboard
- popout.html: same dual-strategy inline
- Fixed: 'Erreur lors de la copie' on HTTP contexts

frontend/js/utils.js

@@ -650,4 +650,34 @@ function initEditor() {
   );
 }
 
-export { getFileIcon, safeCreateIcons, flushIcons, safeHighlight, escapeHtml, EXT_ICONS, openEditor, closeEditor, saveFile, deleteFile, waitForCodeMirror, initEditor };
+function safeHighlight(block) {
+  try { hljs.highlightElement(block); } catch (e) { /* skip */ }
+}
+
+/** Copy text to clipboard — works on both HTTP and HTTPS */
+function copyToClipboard(text) {
+  // Try modern API first (HTTPS-only)
+  if (navigator.clipboard && window.isSecureContext) {
+    navigator.clipboard.writeText(text).catch(() => {});
+    return true;
+  }
+  // Fallback for HTTP contexts
+  const ta = document.createElement("textarea");
+  ta.value = text;
+  ta.style.position = "fixed";
+  ta.style.left = "-9999px";
+  ta.style.top = "-9999px";
+  document.body.appendChild(ta);
+  ta.focus();
+  ta.select();
+  try {
+    document.execCommand("copy");
+    return true;
+  } catch (e) {
+    return false;
+  } finally {
+    document.body.removeChild(ta);
+  }
+}
+
+export { getFileIcon, safeCreateIcons, flushIcons, safeHighlight, escapeHtml, EXT_ICONS, openEditor, closeEditor, saveFile, deleteFile, waitForCodeMirror, initEditor, copyToClipboard };

frontend/js/viewer.js

@@ -681,16 +681,16 @@ export function renderFile(data) {
     wrapper.appendChild(pre);
 
     const btn = el("button", { class: "copy-code-btn", title: "Copier le code" }, [document.createTextNode("Copier")]);
-    btn.addEventListener("click", async (e) => {
+    btn.addEventListener("click", (e) => {
       e.stopPropagation();
       const code = pre.querySelector("code")?.textContent || pre.textContent;
-      try {
-        await navigator.clipboard.writeText(code);
+      const copied = copyToClipboard(code);
+      if (copied) {
         btn.textContent = "✓ Copié";
         btn.classList.add("copied");
         if (typeof showToast === "function") showToast("Code copié dans le presse-papiers", "success");
         setTimeout(() => { btn.textContent = "Copier"; btn.classList.remove("copied"); }, 2000);
-      } catch {
+      } else {
         if (typeof showToast === "function") showToast("Erreur lors de la copie", "error");
       }
     });

frontend/popout.html

@@ -913,11 +913,26 @@ const RightSidebarManager = {
             btn.addEventListener('click', function(e) {
               e.stopPropagation();
               var code = (pre.querySelector('code') || pre).textContent;
-              navigator.clipboard.writeText(code).then(function() {
+              var ok = false;
+              // Try modern API first (HTTPS)
+              if (navigator.clipboard && window.isSecureContext) {
+                navigator.clipboard.writeText(code).then(function() { ok = true; }).catch(function() {});
+              } else {
+                // Fallback for HTTP
+                var ta = document.createElement('textarea');
+                ta.value = code;
+                ta.style.position = 'fixed';
+                ta.style.left = '-9999px';
+                document.body.appendChild(ta);
+                ta.focus(); ta.select();
+                try { document.execCommand('copy'); ok = true; } catch(er) {}
+                document.body.removeChild(ta);
+              }
+              if (ok) {
                 btn.textContent = '✓ Copié';
                 btn.classList.add('copied');
                 setTimeout(function() { btn.textContent = 'Copier'; btn.classList.remove('copied'); }, 2000);
-              }).catch(function() {});
+              }
             });
             wrapper.appendChild(btn);
           });