move exposed objects to classes

[tombl]

theoretically you could forge a html object if you got your hands on the html_tag (e.g. via Object.getOwnPropertySymbols).

private properties are unforgeable, so now everything must go through the intended constructor.

does this meaningfully improve security/size?

[github-actions]

Size Change: +103 B (+3%)

Total Size: 3.54 kB

Filename	Size	Change
./dist/client.min.js	2.05 kB	+10 B (+0.49%)
./dist/server.min.js	776 B	+14 B (+1.84%)
./dist/shared.min.js	644 B	+79 B (+13.98%)	⚠️

ℹ️ View Unchanged

Filename	Size
./dist/index.min.js	63 B

_{compressed-size-action}