Add custom logging framework and debug option

modules/logger.jsm

@@ -0,0 +1,26 @@
+var EXPORTED_SYMBOLS = ['aiLog', 'setDebug'];
+let debugEnabled = false;
+
+function setDebug(value) {
+    debugEnabled = !!value;
+}
+
+function getCaller() {
+    try {
+        let stack = new Error().stack.split('\n');
+        if (stack.length >= 3) {
+            return stack[2].trim().replace(/^@?\s*\(?/,'').replace(/^at\s+/, '');
+        }
+    } catch (e) {}
+    return '';
+}
+
+function aiLog(message, opts = {}, ...args) {
+    const { level = 'log', debug = false } = opts;
+    if (debug && !debugEnabled) {
+        return;
+    }
+    const caller = getCaller();
+    const prefix = caller ? `[ai-filter][${caller}]` : '[ai-filter]';
+    console[level](`%c${prefix}`, 'color:#1c92d2;font-weight:bold', message, ...args);
+}