🧹 Remove unused legacy modules and functions

- Deleted quota.rs module (quota management not needed via HTTP)
- Removed legacy get_id_by_token GraphQL function
- Removed unused set_user_quota and increase_user_quota methods
- Cleaned up unused imports and legacy structs
- Simplified handlers/mod.rs to only expose universal_handler

Architecture now focused on core functionality:
- GET / (user info)
- GET /<filename> (file serving)
- POST / (file upload)

src/handlers/mod.rs

@@ -1,13 +1,10 @@
 mod proxy;
-mod quota;
 mod serve_file;
 mod upload;
 mod user;
+mod universal;
 
-pub use proxy::proxy_handler;
-pub use quota::{get_quota_handler, increase_quota_handler, set_quota_handler};
-pub use upload::upload_handler;
-pub use user::get_current_user_handler;
+pub use universal::universal_handler;
 
-// Общий лимит квоты на пользователя: 5 ГБ
-pub const MAX_USER_QUOTA_BYTES: u64 = 5 * 1024 * 1024 * 1024;
+// Общий лимит квоты на пользователя: 12 ГБ
+pub const MAX_USER_QUOTA_BYTES: u64 = 12 * 1024 * 1024 * 1024;