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/lib/replace/Url.js

@@ -1,33 +1,4 @@
-var UNICODE = '\\\\[0-9a-f]{1,6}(\\r\\n|[ \\n\\r\\t\\f])?';
-var ESCAPE = '(' + UNICODE + '|\\\\[^\\n\\r\\f0-9a-fA-F])';
-var NONPRINTABLE = '\u0000\u0008\u000b\u000e-\u001f\u007f';
-var SAFE_URL = new RegExp('^(' + ESCAPE + '|[^\"\'\\(\\)\\\\\\s' + NONPRINTABLE + '])*$', 'i');
-
-module.exports = function(node) {
-    var value = node.value;
-
-    if (value.type !== 'String') {
-        return;
-    }
-
-    var quote = value.value[0];
-    var url = value.value.substr(1, value.value.length - 2);
-
+export default function(node) {
     // convert `\\` to `/`
-    url = url.replace(/\\\\/g, '/');
-
-    // remove quotes when safe
-    // https://www.w3.org/TR/css-syntax-3/#url-unquoted-diagram
-    if (SAFE_URL.test(url)) {
-        node.value = {
-            type: 'Raw',
-            loc: node.value.loc,
-            value: url
-        };
-    } else {
-        // use double quotes if string has no double quotes
-        // otherwise use original quotes
-        // TODO: make better quote type selection
-        node.value.value = url.indexOf('"') === -1 ? '"' + url + '"' : quote + url + quote;
-    }
+    node.value = node.value.replace(/\\/g, '/');
 };