feat: interactive provider wizard with fast model selection

Adds interactive provider setup wizard.

rust/crates/runtime/src/config.rs

@@ -592,6 +592,92 @@ pub fn default_config_home() -> PathBuf {
         .unwrap_or_else(|| PathBuf::from(".claw"))
 }
 
+/// Save provider settings to the user-level `~/.claw/settings.json`.
+/// Creates the file and directory if they don't exist. Sets file permissions
+/// to `0o600` (owner read/write only) to protect stored API keys.
+pub fn save_user_provider_settings(
+    kind: &str,
+    api_key: &str,
+    base_url: Option<&str>,
+    model: Option<&str>,
+) -> Result<(), ConfigError> {
+    let config_home = default_config_home();
+    fs::create_dir_all(&config_home).map_err(ConfigError::Io)?;
+    let settings_path = config_home.join("settings.json");
+
+    let mut root = read_settings_root(&settings_path);
+
+    let mut provider = serde_json::Map::new();
+    provider.insert("kind".to_string(), serde_json::Value::String(kind.to_string()));
+    provider.insert("apiKey".to_string(), serde_json::Value::String(api_key.to_string()));
+    if let Some(base_url) = base_url {
+        provider.insert("baseUrl".to_string(), serde_json::Value::String(base_url.to_string()));
+    } else {
+        provider.remove("baseUrl");
+    }
+    root.insert("provider".to_string(), serde_json::Value::Object(provider));
+    if let Some(model) = model {
+        root.insert("model".to_string(), serde_json::Value::String(model.to_string()));
+    } else {
+        root.remove("model");
+    }
+
+    write_settings_root(&settings_path, &root)?;
+
+    #[cfg(unix)]
+    {
+        use std::os::unix::fs::PermissionsExt;
+        let perms = std::fs::Permissions::from_mode(0o600);
+        fs::set_permissions(&settings_path, perms).map_err(ConfigError::Io)?;
+    }
+
+    Ok(())
+}
+
+/// Remove the `provider` section from the user-level `~/.claw/settings.json`.
+pub fn clear_user_provider_settings() -> Result<(), ConfigError> {
+    let config_home = default_config_home();
+    let settings_path = config_home.join("settings.json");
+
+    if !settings_path.exists() {
+        return Ok(());
+    }
+
+    let mut root = read_settings_root(&settings_path);
+    if root.remove("provider").is_none() {
+        return Ok(());
+    }
+    root.remove("model");
+
+    write_settings_root(&settings_path, &root)?;
+
+    Ok(())
+}
+
+fn read_settings_root(path: &Path) -> serde_json::Map<String, serde_json::Value> {
+    match fs::read_to_string(path) {
+        Ok(contents) if !contents.trim().is_empty() => {
+            serde_json::from_str::<serde_json::Value>(&contents)
+                .ok()
+                .and_then(|v| v.as_object().cloned())
+                .unwrap_or_default()
+        }
+        _ => serde_json::Map::new(),
+    }
+}
+
+fn write_settings_root(
+    path: &Path,
+    root: &serde_json::Map<String, serde_json::Value>,
+) -> Result<(), ConfigError> {
+    if let Some(parent) = path.parent() {
+        fs::create_dir_all(parent).map_err(ConfigError::Io)?;
+    }
+    let rendered = serde_json::to_string_pretty(&serde_json::Value::Object(root.clone()))
+        .map_err(|e| ConfigError::Parse(e.to_string()))?;
+    fs::write(path, format!("{rendered}\n")).map_err(ConfigError::Io)
+}
+
 impl RuntimeHookConfig {
     #[must_use]
     pub fn new(