Refactor codebase for consistency and readability

- Standardize array and vector formatting for clarity.
- Adjust spacing and indentation in examples and TUI code.
- Ensure proper newline usage across files (e.g., LICENSE, TOML files, etc.).
- Simplify `.to_string()` and `.ok()` calls for brevity.

examples/basic_chat.rs

@@ -1,9 +1,9 @@
 // This example demonstrates a basic chat interaction without the TUI.
 
 use owlen_core::model::Model;
+use owlen_core::provider::Provider;
 use owlen_core::session::Session;
 use owlen_ollama::OllamaProvider; // Assuming you have an Ollama provider
-use owlen_core::provider::Provider;
 
 #[tokio::main]
 async fn main() -> Result<(), anyhow::Error> {