a11y: Web Interface Guidelines — 19 правок доступности и семантики

- base.html: lang динамический, meta theme-color, skip-link, убран дубль Dashboard
- Фильтры: labels на search/select, type=search, placeholder с …, autocomplete=off
- llm-retry: <span> → <button> во всех шаблонах (_llm_report, scan, package)
- sortable th: tabindex=0, role=button через JS + keyboard handler
- sort-icon: aria-hidden=true
- style.css: color-scheme:dark, prefers-reduced-motion, tabular-nums, touch-action
- app.js: clipboard fallback для не-HTTPS

guarddog_nexus/web/static/app.js

@@ -1,14 +1,45 @@
 // GuardDog Nexus — shared UI utilities
 
+document.addEventListener('DOMContentLoaded', function () {
+    document.querySelectorAll('th.sortable').forEach(function (th) {
+        th.setAttribute('tabindex', '0');
+        th.setAttribute('role', 'button');
+    });
+});
+
+document.addEventListener('keydown', function (e) {
+    if ((e.key === 'Enter' || e.key === ' ') && e.target.matches('th.sortable')) {
+        e.preventDefault();
+        e.target.click();
+    }
+});
+
 function copyCode(btn, codeId) {
     var el = document.getElementById(codeId);
     if (!el) return;
-    navigator.clipboard.writeText(el.textContent).then(function () {
-        btn.textContent = 'Copied!';
-        btn.classList.add('copied');
-        setTimeout(function () {
-            btn.textContent = 'Copy';
-            btn.classList.remove('copied');
-        }, 2000);
-    });
+    if (navigator.clipboard) {
+        navigator.clipboard.writeText(el.textContent).then(function () {
+            showCopied(btn);
+        });
+    } else {
+        // Fallback for non-HTTPS
+        var ta = document.createElement('textarea');
+        ta.value = el.textContent;
+        ta.style.position = 'fixed';
+        ta.style.left = '-9999px';
+        document.body.appendChild(ta);
+        ta.select();
+        document.execCommand('copy');
+        document.body.removeChild(ta);
+        showCopied(btn);
+    }
+}
+
+function showCopied(btn) {
+    btn.textContent = 'Copied!';
+    btn.classList.add('copied');
+    setTimeout(function () {
+        btn.textContent = 'Copy';
+        btn.classList.remove('copied');
+    }, 2000);
 }