…rt (#4580)

Addresses feedback from [PR
#4592](#4592 (comment))
regarding inefficient double formatting of Go files during project
generation.

## Changes

- Replace `format.Node` with `printer.Fprint` in AST replacer to skip
intermediate formatting
- Defer all formatting to final `utils.GoFmt` call which uses
`golang.org/x/tools/imports`

Previously, files modified by the AST replacer were formatted twice—once
during import path replacement and again by the final `utils.GoFmt`
call. Now the AST replacer writes unformatted AST, and a single
`utils.GoFmt` pass handles both formatting and import organization.

```go
// Before: formatted output
if err := format.Node(&buf, r.fset, file); err != nil {
    return err
}

// After: unformatted output, formatting deferred
if err := printer.Fprint(&buf, r.fset, file); err != nil {
    return err
}
```

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Co-authored-by: copilot-swe-agent[bot] <[email protected]>
Co-authored-by: hailaz <[email protected]>