FRE-4517, FRE-4499: Complete SpamShield implementation and billing updates

- SpamFeedback table migration with timestamp index
- Real-time interception engine completion
- Billing service enhancements
- Classifier and rule engine updates

Co-Authored-By: Paperclip <noreply@paperclip.ing>

test-classifier.ts

@@ -0,0 +1,60 @@
+import { BertSmsClassifier } from './services/spamshield/src/classifier/sms-classifier';
+
+// Mock SpamShieldService for testing
+class MockSpamShield {
+  async checkReputation(phoneNumber: string) {
+    return {
+      score: 0,
+      isSpam: false,
+      source: 'fallback',
+    };
+  }
+}
+
+async function testClassifier(): Promise<void> {
+  console.log('=== SMS Classifier Feature Flag Test ===\n');
+  
+  // Test 1: Classifier with enabled feature flag
+  console.log('Test 1: Classifier with enabled feature flag');
+  const mockShield = new MockSpamShield();
+  const classifier = new BertSmsClassifier(mockShield as any);
+  
+  const result = await classifier.classify(
+    'Congratulations! You have won $1,000,000! Click here: http://bit.ly/12345 to claim your prize now! Call 555-1234 immediately!'
+  );
+  
+  console.log('Input:', result.body);
+  console.log('Classification:', result.isSpam ? 'SPAM' : 'NOT SPAM');
+  console.log('Score:', result.score);
+  console.log('Features:', result.features);
+  console.log('');
+  
+  // Test 2: Classifier with benign message
+  console.log('Test 2: Classifier with benign message');
+  const benignResult = await classifier.classify(
+    'Hello! Just checking in to see how you are doing. Hope you have a great day!'
+  );
+  
+  console.log('Input:', benignResult.body);
+  console.log('Classification:', benignResult.isSpam ? 'SPAM' : 'NOT SPAM');
+  console.log('Score:', benignResult.score);
+  console.log('');
+  
+  // Test 3: Classifier metrics
+  console.log('Test 3: Classifier metrics');
+  const metrics = classifier.getMetrics();
+  console.log('Total classified:', metrics.totalClassified);
+  console.log('Spam detected:', metrics.spamDetected);
+  console.log('Accuracy:', metrics.totalClassified > 0 
+    ? ((metrics.spamDetected / metrics.totalClassified) * 100).toFixed(1) + '%'
+    : '0%');
+  console.log('');
+  
+  console.log('=== All tests completed successfully ===');
+}
+
+export { testClassifier };
+
+if (import.meta.env?.MODE !== 'test') {
+  testClassifier().catch(console.error);
+}