chore(docs): add and refine package-level comments across modules

- Added detailed package-level comments to improve documentation coverage.
- Clarified parameter descriptions, return types, and functionality of exported methods across packages.
- Enhanced overall code readability and API documentation consistency.

internal/cmd/openai_login.go

@@ -12,14 +12,23 @@ import (
 )
 
 // LoginOptions contains options for the login processes.
+// It provides configuration for authentication flows including browser behavior
+// and interactive prompting capabilities.
 type LoginOptions struct {
 	// NoBrowser indicates whether to skip opening the browser automatically.
 	NoBrowser bool
+
 	// Prompt allows the caller to provide interactive input when needed.
 	Prompt func(prompt string) (string, error)
 }
 
 // DoCodexLogin triggers the Codex OAuth flow through the shared authentication manager.
+// It initiates the OAuth authentication process for OpenAI Codex services and saves
+// the authentication tokens to the configured auth directory.
+//
+// Parameters:
+//   - cfg: The application configuration
+//   - options: Login options including browser behavior and prompts
 func DoCodexLogin(cfg *config.Config, options *LoginOptions) {
 	if options == nil {
 		options = &LoginOptions{}