feat(tui): add markdown rendering support and toggle command

- Introduce new `owlen-markdown` crate that converts Markdown strings to `ratatui::Text` with headings, lists, bold/italic, and inline code.
- Add `render_markdown` config option (default true) and expose it via `app.render_markdown_enabled()`.
- Implement `:markdown [on|off]` command to toggle markdown rendering.
- Update help overlay to document the new markdown toggle.
- Adjust UI rendering to conditionally apply markdown styling based on the markdown flag and code mode.
- Wire the new crate into `owlen-tui` Cargo.toml.

crates/owlen-cli/src/cloud.rs

@@ -221,10 +221,11 @@ fn ensure_provider_entry(config: &mut Config, provider: &str, endpoint: &str) {
     if provider == "ollama"
         && config.providers.contains_key("ollama-cloud")
         && !config.providers.contains_key("ollama")
-        && let Some(mut legacy) = config.providers.remove("ollama-cloud")
     {
-        legacy.provider_type = "ollama".to_string();
-        config.providers.insert("ollama".to_string(), legacy);
+        if let Some(mut legacy) = config.providers.remove("ollama-cloud") {
+            legacy.provider_type = "ollama".to_string();
+            config.providers.insert("ollama".to_string(), legacy);
+        }
     }
 
     core_config::ensure_provider_config(config, provider);
@@ -315,8 +316,10 @@ fn unlock_vault(path: &Path) -> Result<encryption::VaultHandle> {
     use std::env;
 
     if path.exists() {
-        if let Ok(password) = env::var("OWLEN_MASTER_PASSWORD")
-            && !password.trim().is_empty()
+        if let Some(password) = env::var("OWLEN_MASTER_PASSWORD")
+            .ok()
+            .map(|value| value.trim().to_string())
+            .filter(|password| !password.is_empty())
         {
             return encryption::unlock_with_password(path.to_path_buf(), &password)
                 .context("Failed to unlock vault with OWLEN_MASTER_PASSWORD");
@@ -356,30 +359,31 @@ async fn hydrate_api_key(
     config: &mut Config,
     manager: Option<&Arc<CredentialManager>>,
 ) -> Result<Option<String>> {
-    if let Some(manager) = manager
-        && let Some(credentials) = manager.get_credentials(OLLAMA_CLOUD_CREDENTIAL_ID).await?
-    {
+    let credentials = match manager {
+        Some(manager) => manager.get_credentials(OLLAMA_CLOUD_CREDENTIAL_ID).await?,
+        None => None,
+    };
+
+    if let Some(credentials) = credentials {
         let key = credentials.api_key.trim().to_string();
         if !key.is_empty() {
             set_env_if_missing("OLLAMA_API_KEY", &key);
             set_env_if_missing("OLLAMA_CLOUD_API_KEY", &key);
         }
 
-        if let Some(cfg) = provider_entry_mut(config)
-            && cfg.base_url.is_none()
-            && !credentials.endpoint.trim().is_empty()
-        {
-            cfg.base_url = Some(credentials.endpoint);
+        let Some(cfg) = provider_entry_mut(config) else {
+            return Ok(Some(key));
+        };
+        if cfg.base_url.is_none() && !credentials.endpoint.trim().is_empty() {
+            cfg.base_url = Some(credentials.endpoint.clone());
         }
         return Ok(Some(key));
     }
 
-    if let Some(cfg) = provider_entry(config)
-        && let Some(key) = cfg
-            .api_key
-            .as_ref()
-            .map(|value| value.trim())
-            .filter(|value| !value.is_empty())
+    if let Some(key) = provider_entry(config)
+        .and_then(|cfg| cfg.api_key.as_ref())
+        .map(|value| value.trim())
+        .filter(|value| !value.is_empty())
     {
         set_env_if_missing("OLLAMA_API_KEY", key);
         set_env_if_missing("OLLAMA_CLOUD_API_KEY", key);

crates/owlen-cli/src/main.rs

@@ -1,3 +1,5 @@
+#![allow(clippy::collapsible_if)] // TODO: Remove once Rust 2024 let-chains are available
+
 //! OWLEN CLI - Chat TUI client
 
 mod cloud;

crates/owlen-cli/src/mcp.rs

@@ -151,8 +151,9 @@ fn handle_list(args: ListArgs) -> Result<()> {
         "", "Scope", "Name", "Transport"
     );
     for entry in scoped {
-        if let Some(target_scope) = filter_scope
-            && entry.scope != target_scope
+        if filter_scope
+            .as_ref()
+            .is_some_and(|target_scope| entry.scope != *target_scope)
         {
             continue;
         }
@@ -186,8 +187,9 @@ fn handle_list(args: ListArgs) -> Result<()> {
             .collect();
 
         for entry in scoped_resources {
-            if let Some(target_scope) = filter_scope
-                && entry.scope != target_scope
+            if filter_scope
+                .as_ref()
+                .is_some_and(|target_scope| entry.scope != *target_scope)
             {
                 continue;
             }