Prompt before overwriting main.go during init

[srexrg]

• Added the confirmMainOverwrite function to prompt the user for confirmation before overwriting an existing main.go file. The function checks if the file exists and asks for explicit user consent via stdin. (cmd/project.go)
• Updated the Create method in the Project struct to call confirmMainOverwrite before creating main.go, aborting the operation if the user declines. (cmd/project.go)

Fixes #112

[CLAassistant]

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