Update webhook integration to use JSON for sending PDF data

Replaces multipart form data handling with JSON payload for the webhook API call, sending PDF content as a base64 encoded string. This change also removes the `busboy` dependency.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: cfbfe47c-0c9a-4ebf-8a41-2937407eccff
Replit-Commit-Checkpoint-Type: full_checkpoint
Replit-Commit-Screenshot-Url: https://storage.googleapis.com/screenshot-production-us-central1/1957c339-2757-4d1f-8e92-e9f71a1ce58e/cfbfe47c-0c9a-4ebf-8a41-2937407eccff/WbfLPZt

package.json

@@ -43,13 +43,11 @@
     "@radix-ui/react-tooltip": "^1.2.0",
     "@tanstack/react-query": "^5.60.5",
     "@types/bcrypt": "^6.0.0",
-    "@types/busboy": "^1.5.4",
     "@types/form-data": "^2.2.1",
     "@types/memoizee": "^0.4.12",
     "@types/node-fetch": "^2.6.13",
     "@types/pg": "^8.15.4",
     "bcrypt": "^6.0.0",
-    "busboy": "^1.6.0",
     "caniuse-lite": "^1.0.30001727",
     "class-variance-authority": "^0.7.1",
     "clsx": "^2.1.1",