refactor(config): remove unused service-info and consolidate on build-info (#297)

[ghzhost]

Summary

Closes #297

• Removes the redundant src/config/service-info.ts module in favor of src/config/build-info.ts as the single metadata source.
• Updates tests/service-info.test.ts to test buildInfo directly alongside the existing health endpoint tests.
• Translates the non-English comment in src/config/build-info.ts to English.
• Preserves identical runtime behavior for GET /api/v1/health and server startup logging.

Verification

• npx vitest run tests/service-info.test.ts tests/health.test.ts tests/health-payload.test.ts passes 100% (14 tests passed).
• Checked for any remaining imports/usages across src/ and tests/.