refactor(cmd): improve error handling in commands and tests

- Add error checking for filepath.Walk and fmt.Scanln in agent.go
- Ignore MkdirAll error in chat.go, add checks in chat_test.go
- Add Scanln error handling in commit.go
- Capture and exit on completion generation errors in completion.go
- Add WriteFile error checks in edit_test.go

cmd/agent.go

@@ -27,7 +27,7 @@ var agentCmd = &cobra.Command{
 		color.Yellow("🔍 Agent mode activated. Scanning project...")
 
 		var files []string
-		filepath.Walk(".", func(path string, info os.FileInfo, err error) error {
+		err := filepath.Walk(".", func(path string, info os.FileInfo, err error) error {
 			if err != nil || info.IsDir() {
 				return err
 			}
@@ -36,6 +36,10 @@ var agentCmd = &cobra.Command{
 			}
 			return nil
 		})
+		if err != nil {
+			color.Red("Failed to scan project: %v", err)
+			os.Exit(1)
+		}
 
 		if len(files) == 0 {
 			color.Yellow("No .go files found.")
@@ -54,7 +58,10 @@ var agentCmd = &cobra.Command{
 
 		fmt.Print("\nProceed with changes? (y/n): ")
 		var confirm string
-		fmt.Scanln(&confirm)
+		if _, err := fmt.Scanln(&confirm); err != nil {
+			color.Red("Failed to read input: %v", err)
+			return
+		}
 		if confirm != "y" && confirm != "Y" {
 			color.Yellow("Aborted.")
 			return
@@ -91,7 +98,10 @@ var agentCmd = &cobra.Command{
 			if !applyAll {
 				fmt.Print("\nApply this file? (y/n/a = all remaining): ")
 				var answer string
-				fmt.Scanln(&answer)
+				if _, err := fmt.Scanln(&answer); err != nil {
+					color.Yellow("Skipped %s (failed to read input)", file)
+					continue
+				}
 				answer = strings.ToLower(strings.TrimSpace(answer))
 
 				if answer == "a" {

cmd/chat.go

@@ -54,7 +54,7 @@ func getChatHistoryFile() string {
 		home = "."
 	}
 	histDir := filepath.Join(home, ".config", "grokkit")
-	os.MkdirAll(histDir, 0755)
+	_ = os.MkdirAll(histDir, 0755) // Ignore error, WriteFile will catch it
 	return filepath.Join(histDir, "chat_history.json")
 }
 

cmd/chat_test.go

@@ -82,9 +82,13 @@ func TestLoadChatHistory_InvalidJSON(t *testing.T) {
 
 	// Create invalid JSON file
 	histDir := filepath.Join(tmpDir, ".config", "grokkit")
-	os.MkdirAll(histDir, 0755)
+	if err := os.MkdirAll(histDir, 0755); err != nil {
+		t.Fatalf("MkdirAll() error: %v", err)
+	}
 	histFile := filepath.Join(histDir, "chat_history.json")
-	os.WriteFile(histFile, []byte("invalid json{{{"), 0644)
+	if err := os.WriteFile(histFile, []byte("invalid json{{{"), 0644); err != nil {
+		t.Fatalf("WriteFile() error: %v", err)
+	}
 
 	history := loadChatHistory()
 	if history != nil {

cmd/commit.go

@@ -38,7 +38,10 @@ var commitCmd = &cobra.Command{
 		color.Cyan("\nProposed commit message:\n%s", msg)
 		var confirm string
 		color.Yellow("Commit with this message? (y/n): ")
-		fmt.Scanln(&confirm)
+		if _, err := fmt.Scanln(&confirm); err != nil {
+			color.Red("Failed to read input: %v", err)
+			return
+		}
 		if confirm != "y" && confirm != "Y" {
 			color.Yellow("Aborted.")
 			return

cmd/completion.go

@@ -49,15 +49,19 @@ PowerShell:
 	ValidArgs:             []string{"bash", "zsh", "fish", "powershell"},
 	Args:                  cobra.MatchAll(cobra.ExactArgs(1), cobra.OnlyValidArgs),
 	Run: func(cmd *cobra.Command, args []string) {
+		var err error
 		switch args[0] {
 		case "bash":
-			cmd.Root().GenBashCompletion(os.Stdout)
+			err = cmd.Root().GenBashCompletion(os.Stdout)
 		case "zsh":
-			cmd.Root().GenZshCompletion(os.Stdout)
+			err = cmd.Root().GenZshCompletion(os.Stdout)
 		case "fish":
-			cmd.Root().GenFishCompletion(os.Stdout, true)
+			err = cmd.Root().GenFishCompletion(os.Stdout, true)
 		case "powershell":
-			cmd.Root().GenPowerShellCompletionWithDesc(os.Stdout)
+			err = cmd.Root().GenPowerShellCompletionWithDesc(os.Stdout)
+		}
+		if err != nil {
+			os.Exit(1)
 		}
 	},
 }

cmd/edit_test.go

@@ -17,7 +17,9 @@ func TestEditCommand(t *testing.T) {
 	defer os.Remove(tmpfile.Name())
 
 	original := []byte("package main\n\nfunc hello() {}\n")
-	os.WriteFile(tmpfile.Name(), original, 0644)
+	if err := os.WriteFile(tmpfile.Name(), original, 0644); err != nil {
+		t.Fatal(err)
+	}
 
 	// Test the core editing logic directly (non-interactive)
 	instruction := "add a comment at the top"
@@ -32,7 +34,9 @@ func TestEditCommand(t *testing.T) {
 	newContent := grok.CleanCodeResponse(raw)
 
 	// Apply the result (this is what the real command does after confirmation)
-	os.WriteFile(tmpfile.Name(), []byte(newContent), 0644)
+	if err := os.WriteFile(tmpfile.Name(), []byte(newContent), 0644); err != nil {
+		t.Fatal(err)
+	}
 
 	// Verify
 	content, _ := os.ReadFile(tmpfile.Name())