style: apply rustfmt to backend codebase

- Apply rustfmt to all Rust source files in backend/
- Fix trailing whitespace inconsistencies
- Standardize formatting across handlers, models, and services
- Improve code readability with consistent formatting

These changes are purely stylistic and do not affect functionality.
All CI checks now pass with proper formatting.

backend/src/middleware/auth.rs

@@ -1,11 +1,11 @@
+use crate::auth::jwt::Claims;
+use crate::config::AppState;
 use axum::{
     extract::{Request, State},
     http::StatusCode,
     middleware::Next,
     response::Response,
 };
-use crate::auth::jwt::Claims;
-use crate::config::AppState;
 
 pub async fn jwt_auth_middleware(
     State(state): State<AppState>,
@@ -13,29 +13,29 @@ pub async fn jwt_auth_middleware(
     next: Next,
 ) -> Result<Response, StatusCode> {
     let headers = req.headers();
-    
+
     // Extract Authorization header
     let auth_header = headers
         .get("Authorization")
         .and_then(|h| h.to_str().ok())
         .ok_or(StatusCode::UNAUTHORIZED)?;
-    
+
     // Check Bearer token format
     if !auth_header.starts_with("Bearer ") {
         return Err(StatusCode::UNAUTHORIZED);
     }
-    
+
     let token = &auth_header[7..]; // Remove "Bearer " prefix
-    
+
     // Verify token
     let claims = state
         .jwt_service
         .validate_token(token)
         .map_err(|_| StatusCode::UNAUTHORIZED)?;
-    
+
     // Add claims to request extensions for handlers to use
     req.extensions_mut().insert(claims);
-    
+
     Ok(next.run(req).await)
 }
 

backend/src/middleware/mod.rs

@@ -1,8 +1,8 @@
 pub mod auth;
 pub mod rate_limit;
 
-pub use rate_limit::general_rate_limit_middleware;
 pub use auth::jwt_auth_middleware;
+pub use rate_limit::general_rate_limit_middleware;
 
 // Simple security headers middleware
 pub async fn security_headers_middleware(
@@ -10,13 +10,19 @@ pub async fn security_headers_middleware(
     next: axum::middleware::Next,
 ) -> axum::response::Response {
     let mut response = next.run(req).await;
-    
+
     let headers = response.headers_mut();
     headers.insert("X-Content-Type-Options", "nosniff".parse().unwrap());
     headers.insert("X-Frame-Options", "DENY".parse().unwrap());
     headers.insert("X-XSS-Protection", "1; mode=block".parse().unwrap());
-    headers.insert("Strict-Transport-Security", "max-age=31536000; includeSubDomains".parse().unwrap());
-    headers.insert("Content-Security-Policy", "default-src 'self'".parse().unwrap());
-    
+    headers.insert(
+        "Strict-Transport-Security",
+        "max-age=31536000; includeSubDomains".parse().unwrap(),
+    );
+    headers.insert(
+        "Content-Security-Policy",
+        "default-src 'self'".parse().unwrap(),
+    );
+
     response
 }

backend/src/middleware/rate_limit.rs

@@ -1,9 +1,4 @@
-use axum::{
-    extract::Request,
-    http::StatusCode,
-    middleware::Next,
-    response::Response,
-};
+use axum::{extract::Request, http::StatusCode, middleware::Next, response::Response};
 
 /// Middleware for general rate limiting
 /// NOTE: Currently a stub implementation. TODO: Implement IP-based rate limiting
@@ -18,10 +13,7 @@ pub async fn general_rate_limit_middleware(
 
 /// Middleware for auth endpoint rate limiting
 /// NOTE: Currently a stub implementation. TODO: Implement IP-based rate limiting
-pub async fn auth_rate_limit_middleware(
-    req: Request,
-    next: Next,
-) -> Result<Response, StatusCode> {
+pub async fn auth_rate_limit_middleware(req: Request, next: Next) -> Result<Response, StatusCode> {
     // TODO: Implement proper rate limiting with IP-based tracking
     // For now, just pass through
     Ok(next.run(req).await)