feat(logging): enhance log visualization with level-specific colors

- Add CSS classes for log levels (info, debug, error, trace, warn) in main.js to color-code log messages based on their severity.
- Modify log.html to include the log level as a class in each log entry's table row for applying the corresponding color styles.

www/log.html

@@ -89,7 +89,7 @@
             const msg = Object.keys(line).reduce((msg, key) => {
                 return KEYS.indexOf(key) < 0 ? `${msg} ${key}=${line[key]}` : msg;
             }, line['message']);
-            return `<tr><td>${ts.toLocaleString()}</td><td>${line['level']}</td><td>${escapeHTML(msg)}</td></tr>`;
+            return `<tr class="${line['level']}"><td>${ts.toLocaleString()}</td><td>${escapeHTML(line['level'])}</td><td>${escapeHTML(msg)}</td></tr>`;
         }).join('');
     }
 

www/main.js

@@ -131,6 +131,13 @@ body.dark-mode textarea::placeholder {
 body.dark-mode hr {
     border-top: 1px solid #444;
 }
+
+.info { color: #0174DF; }
+.debug { color: #808080; }
+.error { color: #DF0101; }
+.trace { color: #585858; }
+.warn { color: #FF9966; }
+
 </style>
 <nav>
     <ul>