generate-blueprint: apply defaults to selected generators

[patchwork-coder]

Fixes #33923

Problem

generate-blueprint --defaults --sub-generators app applies defaults to the top-level configuration, but still prompts for each selected sub-generator. This blocks unattended blueprint upgrades and exits with ExitPromptError in non-interactive environments.

Change

Apply defaultSubGeneratorConfig() to every selected built-in and additional sub-generator when --defaults is enabled. Duplicate selections are collapsed before initializing their storage.

A regression test supplies conflicting prompt answers and verifies that the stored per-generator values remain the documented defaults, proving the prompts are skipped.

Verification

• Manual reproduction before the patch: command stops at "Is app generator a side-by-side blueprint?"
• Manual verification after the patch: the same command completes and generates the blueprint without interaction
• npx esmocha generators/generate-blueprint/generator.spec.ts --no-parallel --no-insight — 26 passing
• npm run lint — passing
• npm run check-types — passing

AI assistance disclosure

OpenAI Codex assisted with reproducing the issue, implementing the focused change, and preparing the regression test. The resulting diff was reviewed and tested locally. Both commits include a Co-authored-by: OpenAI Codex <[email protected]> trailer.

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