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>

packages/shared-billing/package.json

@@ -9,9 +9,9 @@
     "lint": "eslint src/"
   },
   "dependencies": {
-    "stripe": "^15.0.0",
-    "zod": "^3.22.0",
-    "express": "^4.18.0"
+    "express": "^4.22.1",
+    "stripe": "^14.25.0",
+    "zod": "^3.25.76"
   },
   "devDependencies": {
     "@types/express": "^4.17.0",