Fix code quality violations and exclude Manifest from checks

Document application modes (development/debug/production)
Add global file drop handler, order column normalization, SPA hash fix
Serve CDN assets via /_vendor/ URLs instead of merging into bundles
Add production minification with license preservation
Improve JSON formatting for debugging and production optimization
Add CDN asset caching with CSS URL inlining for production builds
Add three-mode system (development, debug, production)
Update Manifest CLAUDE.md to reflect helper class architecture
Refactor Manifest.php into helper classes for better organization
Pre-manifest-refactor checkpoint: Add app_mode documentation

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

node_modules/csso/cjs/restructure/1-mergeAtrule.cjs

@@ -0,0 +1,109 @@
+'use strict';
+
+const cssTree = require('css-tree');
+
+const { hasOwnProperty } = Object.prototype;
+
+function addRuleToMap(map, item, list, single) {
+    const node = item.data;
+    const name = cssTree.keyword(node.name).basename;
+    const id = node.name.toLowerCase() + '/' + (node.prelude ? node.prelude.id : null);
+
+    if (!hasOwnProperty.call(map, name)) {
+        map[name] = Object.create(null);
+    }
+
+    if (single) {
+        delete map[name][id];
+    }
+
+    if (!hasOwnProperty.call(map[name], id)) {
+        map[name][id] = new cssTree.List();
+    }
+
+    map[name][id].append(list.remove(item));
+}
+
+function relocateAtrules(ast, options) {
+    const collected = Object.create(null);
+    let topInjectPoint = null;
+
+    ast.children.forEach(function(node, item, list) {
+        if (node.type === 'Atrule') {
+            const name = cssTree.keyword(node.name).basename;
+
+            switch (name) {
+                case 'keyframes':
+                    addRuleToMap(collected, item, list, true);
+                    return;
+
+                case 'media':
+                    if (options.forceMediaMerge) {
+                        addRuleToMap(collected, item, list, false);
+                        return;
+                    }
+                    break;
+            }
+
+            if (topInjectPoint === null &&
+                name !== 'charset' &&
+                name !== 'import') {
+                topInjectPoint = item;
+            }
+        } else {
+            if (topInjectPoint === null) {
+                topInjectPoint = item;
+            }
+        }
+    });
+
+    for (const atrule in collected) {
+        for (const id in collected[atrule]) {
+            ast.children.insertList(
+                collected[atrule][id],
+                atrule === 'media' ? null : topInjectPoint
+            );
+        }
+    }
+}
+function isMediaRule(node) {
+    return node.type === 'Atrule' && node.name === 'media';
+}
+
+function processAtrule(node, item, list) {
+    if (!isMediaRule(node)) {
+        return;
+    }
+
+    const prev = item.prev && item.prev.data;
+
+    if (!prev || !isMediaRule(prev)) {
+        return;
+    }
+
+    // merge @media with same query
+    if (node.prelude &&
+        prev.prelude &&
+        node.prelude.id === prev.prelude.id) {
+        prev.block.children.appendList(node.block.children);
+        list.remove(item);
+
+        // TODO: use it when we can refer to several points in source
+        // prev.loc = {
+        //     primary: prev.loc,
+        //     merged: node.loc
+        // };
+    }
+}
+
+function rejoinAtrule(ast, options) {
+    relocateAtrules(ast, options);
+
+    cssTree.walk(ast, {
+        visit: 'Atrule',
+        reverse: true,
+        enter: processAtrule
+    });
+}
+
+module.exports = rejoinAtrule;