Refactor and clean up code across multiple modules

- Simplified token type assignment in OAuth service.
- Removed unused session_lock module and re-exported Session from zesdex_entities.
- Cleaned up session entity by removing unnecessary comments and code.
- Consolidated session handling in HTTP handlers for better readability.
- Improved formatting and readability in OAuth repository tests.
- Enhanced session lock repository with clearer match statements.
- Streamlined session repository error handling.
- Refined RNG tests for better clarity.
- Adjusted module visibility and organization in lib.rs.
- Updated IPC client and connection code for better error handling and clarity.
- Improved frame handling in IPC for better readability.
- Organized module imports and added test utilities for IPC.
- Enhanced database connection error handling.
- Simplified JWT token creation error handling.
- Improved password verification error handling.
- Cleaned up state management code for better readability.
- Refactored middleware for session authentication and rate limiting.
- Simplified clipboard utility for better error handling.
- Enhanced logging initialization for better error reporting.
- Improved pagination utility with clearer method annotations.
- Cleaned up sanitization functions for filenames and paths.
- Enhanced slug generation functions for better clarity and usability.

crates/zesdex-backend/src/app/runtime/context/window.rs

@@ -43,9 +43,11 @@ mod tests {
                 temperature: None,
             },
         );
-        let mut settings = Settings::default();
-        settings.provider = "zen".to_string();
-        settings.model = "deepseek-v4-flash-free".to_string();
+        let settings = Settings {
+            provider: "zen".to_string(),
+            model: "deepseek-v4-flash-free".to_string(),
+            ..Default::default()
+        };
 
         assert_eq!(resolve(&app_config, &settings), 128_000);
     }
@@ -53,9 +55,11 @@ mod tests {
     #[test]
     fn falls_back_to_default_context_window_when_no_role_matches() {
         let app_config = AppConfig::default();
-        let mut settings = Settings::default();
-        settings.provider = "nonexistent".to_string();
-        settings.model = "nonexistent-model".to_string();
+        let settings = Settings {
+            provider: "nonexistent".to_string(),
+            model: "nonexistent-model".to_string(),
+            ..Default::default()
+        };
 
         assert_eq!(
             resolve(&app_config, &settings),
@@ -76,9 +80,11 @@ mod tests {
                 temperature: None,
             },
         );
-        let mut settings = Settings::default();
-        settings.provider = "zen".to_string();
-        settings.model = "deepseek-v4-flash-free".to_string();
+        let settings = Settings {
+            provider: "zen".to_string(),
+            model: "deepseek-v4-flash-free".to_string(),
+            ..Default::default()
+        };
 
         assert_eq!(
             resolve(&app_config, &settings),