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/css-tree/cjs/utils/string.cjs

@@ -0,0 +1,99 @@
+'use strict';
+
+const charCodeDefinitions = require('../tokenizer/char-code-definitions.cjs');
+const utils = require('../tokenizer/utils.cjs');
+
+const REVERSE_SOLIDUS = 0x005c; // U+005C REVERSE SOLIDUS (\)
+const QUOTATION_MARK = 0x0022;  // "
+const APOSTROPHE = 0x0027;      // '
+
+function decode(str) {
+    const len = str.length;
+    const firstChar = str.charCodeAt(0);
+    const start = firstChar === QUOTATION_MARK || firstChar === APOSTROPHE ? 1 : 0;
+    const end = start === 1 && len > 1 && str.charCodeAt(len - 1) === firstChar ? len - 2 : len - 1;
+    let decoded = '';
+
+    for (let i = start; i <= end; i++) {
+        let code = str.charCodeAt(i);
+
+        if (code === REVERSE_SOLIDUS) {
+            // special case at the ending
+            if (i === end) {
+                // if the next input code point is EOF, do nothing
+                // otherwise include last quote as escaped
+                if (i !== len - 1) {
+                    decoded = str.substr(i + 1);
+                }
+                break;
+            }
+
+            code = str.charCodeAt(++i);
+
+            // consume escaped
+            if (charCodeDefinitions.isValidEscape(REVERSE_SOLIDUS, code)) {
+                const escapeStart = i - 1;
+                const escapeEnd = utils.consumeEscaped(str, escapeStart);
+
+                i = escapeEnd - 1;
+                decoded += utils.decodeEscaped(str.substring(escapeStart + 1, escapeEnd));
+            } else {
+                // \r\n
+                if (code === 0x000d && str.charCodeAt(i + 1) === 0x000a) {
+                    i++;
+                }
+            }
+        } else {
+            decoded += str[i];
+        }
+    }
+
+    return decoded;
+}
+
+// https://drafts.csswg.org/cssom/#serialize-a-string
+// § 2.1. Common Serializing Idioms
+function encode(str, apostrophe) {
+    const quote = apostrophe ? '\'' : '"';
+    const quoteCode = apostrophe ? APOSTROPHE : QUOTATION_MARK;
+    let encoded = '';
+    let wsBeforeHexIsNeeded = false;
+
+    for (let i = 0; i < str.length; i++) {
+        const code = str.charCodeAt(i);
+
+        // If the character is NULL (U+0000), then the REPLACEMENT CHARACTER (U+FFFD).
+        if (code === 0x0000) {
+            encoded += '\uFFFD';
+            continue;
+        }
+
+        // If the character is in the range [\1-\1f] (U+0001 to U+001F) or is U+007F,
+        // the character escaped as code point.
+        // Note: Do not compare with 0x0001 since 0x0000 is precessed before
+        if (code <= 0x001f || code === 0x007F) {
+            encoded += '\\' + code.toString(16);
+            wsBeforeHexIsNeeded = true;
+            continue;
+        }
+
+        // If the character is '"' (U+0022) or "\" (U+005C), the escaped character.
+        if (code === quoteCode || code === REVERSE_SOLIDUS) {
+            encoded += '\\' + str.charAt(i);
+            wsBeforeHexIsNeeded = false;
+        } else {
+            if (wsBeforeHexIsNeeded && (charCodeDefinitions.isHexDigit(code) || charCodeDefinitions.isWhiteSpace(code))) {
+                encoded += ' ';
+            }
+
+            // Otherwise, the character itself.
+            encoded += str.charAt(i);
+            wsBeforeHexIsNeeded = false;
+        }
+    }
+
+    return quote + encoded + quote;
+}
+
+exports.decode = decode;
+exports.encode = encode;