refresh-sig-hoc-chain.md

@prefresh/vite	patch
@prefresh/core	patch

Align $RefreshSig$ with React's HOC-chain design to fix memo-wrapped components

Both Babel and Oxc emit two _s(…, key) calls for a memo-wrapped component (_s(memo(_c = _s(inner, key)), key)). The previous status-machine approach mishandled the second keyed call, crashing with "Cannot set properties of undefined" because the outer type had not yet been registered when sign was called with 'needsHooks'.

The new implementation follows the same pattern as createSignatureFunctionForTransform in vite-plugin-react:

• Discriminate by typeof key === 'string' instead of a mutable status variable.
• Always call sign with 'begin' for every keyed call, regardless of position in the HOC chain.
• Track savedType (the innermost type) and defer 'needsHooks' collection to the first no-argument body call, guarded by a didCollectHooks flag.

@prefresh/core's sign is also made idempotent on the 'begin' path so that the inner type's getCustomHooks is never overwritten by an outer HOC call that carries no hook information, and the 'needsHooks' path is guarded against a missing signature entry.