docs(client): add documentation comments to Client struct and methods

Add detailed GoDoc-style comments for the Client struct, NewClient function,
and various streaming methods to improve code readability and documentation.
Also include a comment for CleanCodeResponse and minor formatting adjustments.

internal/grok/client.go

@@ -16,11 +16,16 @@ import (
 	"gmgauthier.com/grokkit/internal/logger"
 )
 
+// Client represents a client for interacting with the XAI API.
+// It holds the API key and base URL for making requests.
 type Client struct {
 	APIKey  string
 	BaseURL string
 }
 
+// NewClient creates and returns a new Client instance.
+// It retrieves the API key from the XAI_API_KEY environment variable.
+// If the variable is not set, it prints an error and exits the program.
 func NewClient() *Client {
 	key := os.Getenv("XAI_API_KEY")
 	if key == "" {
@@ -33,17 +38,23 @@ func NewClient() *Client {
 	}
 }
 
-// Stream prints live to terminal (used by non-TUI commands)
+// Stream sends a streaming chat completion request to the API and prints the response live to the terminal.
+// It uses a default temperature of 0.7. This is intended for non-TUI commands.
+// Returns the full response text.
 func (c *Client) Stream(messages []map[string]string, model string) string {
 	return c.StreamWithTemp(messages, model, 0.7)
 }
 
-// StreamWithTemp allows specifying temperature
+// StreamWithTemp sends a streaming chat completion request to the API with a specified temperature
+// and prints the response live to the terminal.
+// Returns the full response text.
 func (c *Client) StreamWithTemp(messages []map[string]string, model string, temperature float64) string {
 	return c.streamInternal(messages, model, temperature, true)
 }
 
-// StreamSilent returns the full text without printing (used by TUI and agent)
+// StreamSilent sends a streaming chat completion request to the API and returns the full response text
+// without printing it live. It uses a default temperature of 0.7.
+// This is intended for TUI and agent use.
 func (c *Client) StreamSilent(messages []map[string]string, model string) string {
 	return c.streamInternal(messages, model, 0.7, false)
 }
@@ -145,7 +156,9 @@ func (c *Client) streamInternal(messages []map[string]string, model string, temp
 	return fullReply.String()
 }
 
-// CleanCodeResponse removes markdown fences and returns pure code content
+// CleanCodeResponse removes Markdown code fences from the input text and returns the pure code content.
+// It removes opening fences (with optional language tags) and closing fences, then trims leading and trailing whitespace.
+// Internal blank lines are preserved as they may be intentional in code.
 func CleanCodeResponse(text string) string {
 	fence := "```"