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/svgo/plugins/removeDeprecatedAttrs.js

@@ -0,0 +1,120 @@
+import * as csswhat from 'css-what';
+import { attrsGroupsDeprecated, elems } from './_collections.js';
+import { collectStylesheet } from '../lib/style.js';
+
+/**
+ * @typedef RemoveDeprecatedAttrsParams
+ * @property {boolean=} removeUnsafe
+ */
+
+export const name = 'removeDeprecatedAttrs';
+export const description = 'removes deprecated attributes';
+
+/**
+ * @param {import('../lib/types.js').Stylesheet} stylesheet
+ * @returns {Set<string>}
+ */
+function extractAttributesInStylesheet(stylesheet) {
+  const attributesInStylesheet = new Set();
+
+  stylesheet.rules.forEach((rule) => {
+    const selectors = csswhat.parse(rule.selector);
+    selectors.forEach((subselector) => {
+      subselector.forEach((segment) => {
+        if (segment.type !== 'attribute') {
+          return;
+        }
+
+        attributesInStylesheet.add(segment.name);
+      });
+    });
+  });
+
+  return attributesInStylesheet;
+}
+
+/**
+ * @param {import('../lib/types.js').XastElement} node
+ * @param {{ safe?: Set<string>; unsafe?: Set<string> }|undefined} deprecatedAttrs
+ * @param {import('../lib/types.js').DefaultPlugins['removeDeprecatedAttrs']} params
+ * @param {Set<string>} attributesInStylesheet
+ */
+function processAttributes(
+  node,
+  deprecatedAttrs,
+  params,
+  attributesInStylesheet,
+) {
+  if (!deprecatedAttrs) {
+    return;
+  }
+
+  if (deprecatedAttrs.safe) {
+    deprecatedAttrs.safe.forEach((name) => {
+      if (attributesInStylesheet.has(name)) {
+        return;
+      }
+      delete node.attributes[name];
+    });
+  }
+
+  if (params.removeUnsafe && deprecatedAttrs.unsafe) {
+    deprecatedAttrs.unsafe.forEach((name) => {
+      if (attributesInStylesheet.has(name)) {
+        return;
+      }
+      delete node.attributes[name];
+    });
+  }
+}
+
+/**
+ * Remove deprecated attributes.
+ *
+ * @type {import('../lib/types.js').Plugin<RemoveDeprecatedAttrsParams>}
+ */
+export function fn(root, params) {
+  const stylesheet = collectStylesheet(root);
+  const attributesInStylesheet = extractAttributesInStylesheet(stylesheet);
+
+  return {
+    element: {
+      enter: (node) => {
+        const elemConfig = elems[node.name];
+        if (!elemConfig) {
+          return;
+        }
+
+        // Special cases
+
+        // Removing deprecated xml:lang is safe when the lang attribute exists.
+        if (
+          elemConfig.attrsGroups.has('core') &&
+          node.attributes['xml:lang'] &&
+          !attributesInStylesheet.has('xml:lang') &&
+          node.attributes['lang']
+        ) {
+          delete node.attributes['xml:lang'];
+        }
+
+        // General cases
+
+        elemConfig.attrsGroups.forEach((attrsGroup) => {
+          processAttributes(
+            node,
+            attrsGroupsDeprecated[attrsGroup],
+            params,
+            attributesInStylesheet,
+          );
+        });
+
+        processAttributes(
+          node,
+          elemConfig.deprecated,
+          params,
+          attributesInStylesheet,
+        );
+      },
+    },
+  };
+}