GHSA-325j-mg25-8q58: yayson: Prototype pollution in Store/LegacyStore deserialization

# Summary `Store`/`LegacyStore` key internal lookup tables by the `type`, `id`, and relationship names from a JSON:API document. Because these were plain objects, a document with `type: "__proto__"` writes onto `Object.prototype`, polluting every object in the process. # Severity Suggested CVSS v3.1 `AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H` (8.1). The guaranteed impact is process-wide DoS / logic corruption; escalation to authorization bypass or RCE is dependent on gadgets in the consuming application. # Affected / Patched - Affected: `<= 4.2.0` (verified in `3.0.0` and `4.2.0`; all 3.x and 4.x).