Add comprehensive documentation and examples for Owlen architecture and usage

- Include detailed architecture overview in `docs/architecture.md`.
- Add `docs/configuration.md`, detailing configuration file structure and settings.
- Provide a step-by-step provider implementation guide in `docs/provider-implementation.md`.
- Add frequently asked questions (FAQ) document in `docs/faq.md`.
- Create `docs/migration-guide.md` for future breaking changes and version upgrades.
- Introduce new examples in `examples/` showcasing basic chat, custom providers, and theming.
- Add a changelog (`CHANGELOG.md`) for tracking significant changes.
- Provide contribution guidelines (`CONTRIBUTING.md`) and a Code of Conduct (`CODE_OF_CONDUCT.md`).

examples/basic_chat.rs

@@ -0,0 +1,30 @@
+// This example demonstrates a basic chat interaction without the TUI.
+
+use owlen_core::model::Model;
+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> {
+    // This example requires a running Ollama instance.
+    // Make sure you have a model available, e.g., `ollama pull llama2`
+
+    let provider = OllamaProvider;
+    let model = Model::new("llama2"); // Change to a model you have
+    let mut session = Session::new("basic-chat-session");
+
+    println!("Starting basic chat with model: {}", model.name);
+
+    let user_message = "What is the capital of France?";
+    session.add_message("user", user_message);
+    println!("User: {}", user_message);
+
+    // Send the chat to the provider
+    let response = provider.chat(&session, &model).await?;
+
+    session.add_message("bot", &response);
+    println!("Bot: {}", response);
+
+    Ok(())
+}