Remove deprecated Nginx configuration for stream.graff.estate and update package dependencies in session-server and client

- Deleted the Nginx configuration file for stream.graff.estate.
- Updated bun.lock files in both client and session-server to include new dependencies and version updates.
- Added 'tree-kill' dependency to session-server for improved process management.
- Refactored process termination logic in session-server to utilize 'tree-kill' for reliable process termination.

session-server/package.json

@@ -12,6 +12,7 @@
     "start": "bun ./dist/index.js"
   },
   "dependencies": {
-    "got": "^14.4.9"
+    "got": "^14.4.9",
+    "tree-kill": "^1.2.2"
   }
 }