fix: resolve all clippy warnings and convert integration_tests to custom cfg

- Add type aliases (FileRow, FolderRow, FolderRowPaginated, FolderRowOptUser) to reduce type complexity
- Simplify redundant closures in app_password_handler and webdav_handler
- Remove needless borrow in auth_handler
- Collapse nested if/let chains in login_lockout, webdav_lock, auth, rate_limit
- Box LockEntry in acquire() Err variant to fix large enum variant warning
- Rename DeviceCodeStatus::from_str to parse to avoid should_implement_trait lint
- Add #[allow(clippy::too_many_arguments)] and #[allow(clippy::result_unit_err)] where appropriate
- Convert integration_tests from cargo feature to custom cfg attribute
- Add check-cfg lint config in Cargo.toml for integration_tests cfg

src/interfaces/middleware/auth.rs

@@ -273,30 +273,29 @@ pub async fn auth_middleware(
 
         if let Some(token_str) =
             cookie_auth::extract_cookie_value(&headers, cookie_auth::ACCESS_COOKIE)
+            && !token_str.is_empty()
         {
-            if !token_str.is_empty() {
-                tracing::debug!("Processing cookie-based authentication");
+            tracing::debug!("Processing cookie-based authentication");
 
-                if let Some(auth_service) = state.auth_service.as_ref() {
-                    let token_service = &auth_service.token_service;
-                    match token_service.validate_token(&token_str) {
-                        Ok(claims) => {
-                            tracing::debug!("Cookie token validated for user: {}", claims.username);
-                            let current_user = CurrentUser {
-                                id: claims.sub,
-                                username: claims.username,
-                                email: claims.email,
-                                role: claims.role,
-                            };
-                            request.extensions_mut().insert(current_user);
-                            request.extensions_mut().insert(CookieAuthenticated);
-                            return Ok(next.run(request).await);
-                        }
-                        Err(e) => {
-                            tracing::debug!("Cookie token validation failed: {}", e);
-                            // Don't return error — fall through to "no token" so
-                            // the browser gets a 401 and can redirect to /login.
-                        }
+            if let Some(auth_service) = state.auth_service.as_ref() {
+                let token_service = &auth_service.token_service;
+                match token_service.validate_token(&token_str) {
+                    Ok(claims) => {
+                        tracing::debug!("Cookie token validated for user: {}", claims.username);
+                        let current_user = CurrentUser {
+                            id: claims.sub,
+                            username: claims.username,
+                            email: claims.email,
+                            role: claims.role,
+                        };
+                        request.extensions_mut().insert(current_user);
+                        request.extensions_mut().insert(CookieAuthenticated);
+                        return Ok(next.run(request).await);
+                    }
+                    Err(e) => {
+                        tracing::debug!("Cookie token validation failed: {}", e);
+                        // Don't return error — fall through to "no token" so
+                        // the browser gets a 401 and can redirect to /login.
                     }
                 }
             }

src/interfaces/middleware/rate_limit.rs

@@ -57,6 +57,7 @@ impl RateLimiter {
 
     /// Check whether the IP is allowed. Returns `Ok(current_count)` or
     /// `Err(StatusCode::TOO_MANY_REQUESTS)`.
+    #[allow(clippy::result_unit_err)]
     pub fn check_and_increment(&self, ip: &str) -> Result<u32, ()> {
         let key = ip.to_string();
         // moka's entry API lets us atomically read-modify-write.
@@ -92,12 +93,12 @@ pub fn extract_client_ip<B>(req: &Request<B>) -> String {
     let headers = req.headers();
 
     // 1. X-Forwarded-For (first entry — closest to the client)
-    if let Some(xff) = headers.get("x-forwarded-for").and_then(|v| v.to_str().ok()) {
-        if let Some(first) = xff.split(',').next() {
-            let ip = first.trim();
-            if !ip.is_empty() {
-                return ip.to_string();
-            }
+    if let Some(xff) = headers.get("x-forwarded-for").and_then(|v| v.to_str().ok())
+        && let Some(first) = xff.split(',').next()
+    {
+        let ip = first.trim();
+        if !ip.is_empty() {
+            return ip.to_string();
         }
     }