fix(create-granite-app): avoid concurrent tool template writes

[juntak45]

Summary

• Apply multiple create-granite-app tool templates through a single package.json merge/write path.
• Keep the existing single-template helper as a compatibility wrapper.
• Add a regression test covering biome + eslint-prettier together.

Test Plan

• cd packages/create-granite-app && yarn exec vitest run src/copyToolTemplate.spec.ts src/transformTemplate.spec.ts src/resolveFallback.spec.ts --root ../..
• yarn nx run create-granite-app:typecheck
• yarn eslint packages/create-granite-app/src/copyToolTemplate.ts packages/create-granite-app/src/copyToolTemplate.spec.ts packages/create-granite-app/src/index.ts
• yarn nx run create-granite-app:build --skip-nx-cache
• Manual smoke: run built create-granite-app with --tools biome --tools eslint-prettier and verify both tool files/dependencies exist

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Latest commit: 9323ad9

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