Add SvelteKit Vite build RBE smoke target

[Jesssullivan]

Summary

• add //:sveltekit_vite_build_smoke as a narrow Bazel js_test for SvelteKit/Vite build execution
• run the build in a copied temporary workspace so generated files stay out of the source checkout
• model local npm workspace package links for the build-relevant @blog/pulse-client / @blog/pulse-core packages and their Aspect npm-store dependencies
• document the build-smoke target and keep the publication/deploy boundary explicit

Validation

• npm ci
• git diff --check
• npx prettier --check scripts/run-sveltekit-vite-build-bazel.mjs README.md
• npx --yes @bazel/bazelisk test --config=ci --config=no-remote-cache //:sveltekit_vite_build_smoke
• GF REAPI Cell Proof 25779597385: //:sveltekit_vite_build_smoke passed with forced execution, 2331 processes: 1477 internal, 855 remote

RBE Evidence

• run: https://github.com/tinyland-inc/GloriousFlywheel/actions/runs/25779597385
• target: //:sveltekit_vite_build_smoke
• executor/cache: grpc://gf-reapi-cell.gf-rbe.svc.cluster.local:8980
• platform: gloriousflywheel-rbe-linux-x86_64
• worker image digest: sha256:a567696e341f6eb0589ece9efd6014a2133a4f10831bdad31e8dd84055eff8a0
• worker: gf-reapi-cell-ff5f7699f-2td2v
• remote test action: external/bazel_tools/tools/test/test-setup.sh sveltekit_vite_build_smoke_/sveltekit_vite_build_smoke, exit 0

Boundary

This proves a minimal public SvelteKit/Vite build target candidate for GloriousFlywheel REAPI evidence. It does not prove default repo-wide RBE, the full hosted Playwright suite, strict Mermaid pre-rendering, Pagefind publication, the full npm prebuild/postbuild publication chain, deployment, or RustFS-backed CAS/action-cache authority.

Linear: TIN-1133