fix(native): one resolved-style cache key per distinct input set

[YevheniiKotyrlo]

Problem

generateStateHash keys the resolved-style cache on weak-key identity, so it shares an entry only when equal inputs arrive as one object. Two defects on main break that:

1. The config is minted per instance. useCssElement derives one from a module constant on every mount, so N identical elements each hold their own cache entry, sorted rule array and observable.
2. The key is a lossy digest. Folding the key numbers into one base-36 number collides, and family returns the entry it holds whatever rules the second caller brought, so a collision renders one element's styles on another.

Solution

• The config is derived once per mapping through weakFamily. A mapping that is not an object is refused by name, rather than failing inside the WeakMap with a message that names neither styled() nor the argument.
• The key numbers are sorted and joined, which is exact and order-independent. They sit in a Float64Array, so the sort is numeric without a comparator and the unbounded key counter does not wrap.
• family gains size(), so the invariant is assertable.

Tests

• config-identity.test.ts and state-hash.test.ts pin the derivation and the key: one mapping gives one config, a mapping that is not an object is refused by name, distinct key sets never share a key, and order does not matter.
• style-cache.test.tsx counts entries for identical and differing elements, and checks that elements sharing an entry and its config each see the value nativeStyleMapping took.
• On main with only size() added, 8 of the 14 cases fail: 50 identical elements hold 50 entries, and three identical buttons hold three. Each of 6 mutations fails its own cases.

Verification

On Windows with Node 26:

• yarn lint clean
• yarn typecheck clean
• yarn test --coverage: every failure also fails on main on this machine (the four babel cases)
• yarn build clean
• yarn example expo export --platform web exported

Merge order

#436 builds on this, so this lands first.

It also shares lines with #412 (native/reactivity.ts); whichever lands second rebases.

Base

Re-written on main (a5002c5). #451 makes family and weakFamily cache on presence, which this fixed too, so that half is gone.

[YevheniiKotyrlo]

No device frame

The change is how many cache entries identical elements share, not what they paint, and the description's tests count them.