feat(demohouse/car-decision-assistant): add car decision assistant

[3494036618-eng]

Summary

• add the self-hosted Car Decision Assistant under demohouse/car-decision-assistant
• add the application entry to the repository root README
• record the canonical upstream release and commit in UPSTREAM.json

The application turns natural-language car-buying requirements into traceable checks against exact vehicle configurations, city-level sales data, and user-confirmed subjective criteria using Agent Plan, Professional Dataset, and AI Native Application Development Foundation.

Source

• Repository: https://github.com/3494036618-eng/car-decision-assistant
• Release: v0.1.0
• Commit: 8d0f557d3758da3c3e8a5830e86e4e868301f3ea
• Source CI: https://github.com/3494036618-eng/car-decision-assistant/actions/runs/30784172357

The imported tree matches the release exactly, except for the added UPSTREAM.json provenance file.

Verification

• npm run release:validate
• npm run release:validate:strict
• npm run skill:validate
• npm run skill:test
• Gitleaks 8.30.1: no leaks found
• git diff --check
• no symbolic links or files larger than 5 MiB
• source release CI: passed

No paid provider calls, cloud-resource writes, or live business acceptance runs were performed for this repository-import PR.