Add Honox framework adapter

Honox support requires a small adapter in packages/core/src/framework/ that maps hono/jsx's reactive primitives to Formisch's internal framework interface — the same pattern used for React, Vue, Solid, Svelte, and Angular.

The file (index.honox.ts) will wire up:

• createSignal — hono/jsx has no built-in signal primitive of its own, so this reuses the same subscriber-set based signal implementation as index.react.ts
• batch — same batching implementation as the other DOM frameworks (collects notifications and flushes them once)
• untrack — same listener-suspend implementation as the other DOM frameworks

This is a purely additive change (~140 lines, mirrors index.react.ts almost verbatim). No existing files are modified.

It's the foundation that frameworks/honox will build on in a follow-up PR.

Also, I've already implemented demo app, I'll be able to submit PR Stacks within these days.