fix(cli): default git init prompt to true on scaffold (#1650)

## Summary

- Flip the default for the `Initialize a git repository with an initial
commit?` prompt from `false` to `true`, matching the pre-commit hooks
prompt and the typical expectation that scaffolded projects start as a
git repo.

Follow-up to #1484 (review comment:
#1484 (comment)).

<img width="1576" height="736" alt="image"
src="https://github.com/user-attachments/assets/1edce33e-b559-40f4-826f-6f35bc77fe48"
/>


## Test plan

- [x] Scaffold a new project interactively and confirm the git-init
prompt is preselected as Yes.

Author: fengmk2

packages/cli/src/utils/prompts.ts

@@ -228,7 +228,7 @@ export async function promptGitInit(options: {
   if (options.interactive) {
     const selected = await prompts.confirm({
       message: 'Initialize a git repository with an initial commit?',
-      initialValue: false,
+      initialValue: true,
     });
     if (prompts.isCancel(selected)) {
       cancelAndExit();