Refactor JS assets into bundled modules

[obenno]

Summary

• move the custom frontend code into modular src/js sources and bundle it with Vite into www/js/synteny.min.js
• manage frontend dependencies with npm, add ESLint checks, and remove vendored browser libraries from www/js
• fix several macro, micro, and dot-view rendering edge cases while reducing repeated tooltip and lookup work

Testing

• npm run lint
• npm run build:js