Classify browser runtime dependencies for transfer review

[chubes4]

Summary

• Add a browser runtime dependency audit that classifies workspace packages and root dependencies by generic runtime, Playground backend, browser actions, plugin packaging, build/smoke, generated asset, and transitive Playground roles.
• Clarify browser runtime asset packaging and provenance, including that caller-provided runtime ingredients stay outside WP Codebox dependencies.
• Extend the package distribution smoke to verify the checked-in browser runtime asset ships in the WordPress plugin zip and keeps generic WP Codebox browser defaults.

Verification

• npm run build && npm run browser-runtime-operation-smoke && npm run wordpress-plugin-smoke && npm run package-distribution-smoke

Closes #358.

AI assistance

• AI assistance: Yes
• Tool(s): OpenCode (openai/gpt-5.5)
• Used for: Drafted the dependency classification documentation, updated package smoke assertions, resolved rebase conflicts, and ran verification; Chris remains responsible for review and merge.