fix: rebuild native addon before release test scripts

[Helweg]

Summary

Ensure the release-gate test scripts rebuild the native addon before Vitest runs so local npm run test:run and npm run test:coverage do not reuse a stale .node binary after Rust changes.

Changes

• add pretest:run to invoke npm run build:native before vitest run
• add pretest:coverage to invoke npm run build:native before vitest run --coverage
• align the documented local release validation path with CI's native-build-before-test behavior

Testing

How were these changes tested?

• Unit tests added/updated
• Manual testing performed
• Build passes (npm run build)
• Typecheck passes (npm run typecheck)
• Tests pass (npm run test:run)
• Lint passes (npm run lint)

Exact validation results:

• npm run build ✅
• npm run typecheck ✅
• npm run lint ✅
• npm run test:run ✅ (25 files, 478 tests passed)
• cargo fmt --check ✅
• cargo clippy -- -D warnings ✅
• cargo test ✅ (58 passed)
• npm run eval:smoke ✅ (Hit@5=0.00%, MRR@10=0.0000, p95=0.178ms)
• npm run test:coverage ✅ (25 files, 478 tests passed)
• tests/call-graph.test.ts PHP call extraction assertions pass after the script-triggered native rebuild
• tests/retrieval-benchmark.test.ts remained green under coverage on this branch (meets Hit@5 and latency budgets); no non-PHP benchmark regression was observed from this change

Release Labels

• Added at least one release category label (feature, bug, performance, documentation, dependencies, refactor, test, chore, or skip-changelog)
• Added at most one semver label (semver:major, semver:minor, semver:patch) when needed

Related Issues

N/A