refactor: Implement file access filtering based on agent permissions

- Introduced `filterFilesByAgentAccess` function to filter files based on user access through agents.
- Updated `getFiles` and `primeFiles` functions to utilize the new filtering logic.
- Moved `hasAccessToFilesViaAgent` function from the File model to permission services, adjusting imports accordingly
- Enhanced tests to ensure proper access control and filtering behavior for files associated with agents.

api/server/services/Files/index.js

@@ -0,0 +1,12 @@
+const { processCodeFile } = require('./Code/process');
+const { processFileUpload } = require('./process');
+const { uploadImageBuffer } = require('./images');
+const { hasAccessToFilesViaAgent, filterFilesByAgentAccess } = require('./permissions');
+
+module.exports = {
+  processCodeFile,
+  processFileUpload,
+  uploadImageBuffer,
+  hasAccessToFilesViaAgent,
+  filterFilesByAgentAccess,
+};