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/tokens.rs

@@ -10,7 +10,7 @@
 //! `o200k_base` is an approximation for non-OpenAI providers but is far
 //! closer than a flat byte-per-token guess; it's only used for the
 //! 85%/95% budget thresholds, not for billing-accurate counts.
-use crate::dto::chat::message::ChatMessage;
+
 
 /// Count tokens in a single string under `o200k_base`.
 ///
@@ -25,20 +25,16 @@ pub fn count_tokens(text: &str) -> usize {
         .len()
 }
 
-/// Count tokens in a `ChatMessage`'s text content.
-///
-/// Return: 0 for a message with no `content` (e.g. an assistant message
-/// that only carries `tool_calls`).
-#[allow(dead_code)]
-pub fn count_message_tokens(msg: &ChatMessage) -> usize {
-    msg.content.as_deref().map_or(0, count_tokens)
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;
     use crate::dto::chat::message::ChatMessage;
 
+    /// Count tokens in a `ChatMessage`'s text content.
+    fn count_message_tokens(msg: &ChatMessage) -> usize {
+        msg.content.as_deref().map_or(0, count_tokens)
+    }
+
     #[test]
     fn empty_string_has_zero_tokens() {
         assert_eq!(count_tokens(""), 0);

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),