fix(package): include wasm artifacts

[ubugeeei]

Summary

• remove wasm-pack generated ignore rules after browser artifact builds
• add an npm pack dry-run assertion for required browser wasm artifacts
• make the fastqr package check target ignore generated wasm output explicitly

Closes #16

Validation

• pnpm install --frozen-lockfile
• vp run fastqr#build-browser
• node npm/fastqr/scripts/check-package-artifacts.mjs --browser
• npm pack --dry-run --json includes wasm/fastqr_wasm.js, wasm/fastqr_wasm_bg.wasm, and declarations

[ubugeeei]

Landed via #27 after local vp run ci and final GitHub Actions CI passed. Closing this issue-scoped PR to keep the queue and PR list clean.