08 Add provider-neutral data and state binding contracts

[artiphishle]

Summary

• adds provider-neutral binding contracts for manifest node props
• adds BindingValueSource for literal, state, context, event, and db.collection sources
• adds DbCollectionQueryBinding reusing DbFilter, DbSort, and DbPage
• supports refresh intent through static, focus, poll, and live
• adds UiNode.bindings?: readonly NodePropBinding[]
• exports the contracts from root and the @ankhorage/contracts/bindings subpath
• adds tests for:
  • a node prop bound to state
  • a node prop bound to a DB collection query
  • literal/context/event value sources
  • refresh intent modes
• adds a changeset

Closes #35.

Notes

This remains provider-neutral and state-engine-neutral. It does not import runtime, ZORA, Supabase, Legend State, React Query, Zustand, SWR, or React.

Verification

Please run locally:

bun run build
bun run lint:fix
bun run test
bun run knip

I could not run local verification from this environment.