Refactor codebase: improve formatting consistency, simplify message rendering, and optimize cursor and visual selection handling logic across panels.

crates/owlen-core/src/formatting.rs

@@ -35,7 +35,12 @@ impl MessageFormatter {
     }
 
     pub fn format_message(&self, message: &Message) -> Vec<String> {
-        message.content.trim().lines().map(|s| s.to_string()).collect()
+        message
+            .content
+            .trim()
+            .lines()
+            .map(|s| s.to_string())
+            .collect()
     }
 
     /// Extract thinking content from <think> tags, returning (content_without_think, thinking_content)