completely refactor the backend

backend/Cargo.toml

@@ -12,11 +12,15 @@ name = "warren_backend"
 path = "src/bin/backend/main.rs"
 
 [dependencies]
+anyhow = "1.0.98"
 axum = { version = "0.8.4", features = ["multipart", "query"] }
+axum_typed_multipart = "0.16.3"
+derive_more = { version = "2.0.1", features = ["display"] }
 dotenv = "0.15.0"
 env_logger = "0.11.8"
 log = "0.4.27"
 mime_guess = "2.0.5"
+regex = "1.11.1"
 serde = { version = "1.0.219", features = ["derive"] }
 serde_json = "1.0.140"
 sqlx = { version = "0.8.6", features = ["postgres", "runtime-tokio", "uuid"] }