fix(store): prevent prototype pollution via setStore paths

[thomasbuilds]

Fixes a prototype-pollution vulnerability in solid-js/store. Any code path that forwards untrusted input into setStore(...), a common pattern for query params, form fields, or JSON bodies, could mutate Object.prototype and affect every object in the runtime.

Reproduction (against main)

import { createStore } from "solid-js/store";
const [state, setState] = createStore({ a: 1 });

setState("__proto__", "polluted", true);
console.log(({}).polluted);        // true  ❌ global pollution

setState("__proto__", { x: true });
console.log(({}).x);               // true  ❌ global pollution

setState("constructor", "prototype", "y", true);
console.log(({}).y);               // true  ❌ global pollution

// Realistic attacker payload:
const evil = JSON.parse('{"__proto__":{"z":true}}');
setState(evil);                    // ❌ redefines the store's prototype

[changeset-bot]

🦋 Changeset detected

Latest commit: dad5b06

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 2 packages

Name	Type
solid-js	Patch
test-integration	Patch

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[ryansolid]

thank you