No oxlint equivalent for eslint-plugin-pinia

[Radiergummi]

The Vue preset applies eslint-plugin-pinia's recommended-flat rules to **/*.vue, **/*.ts and **/*.tsx. oxlint has no Pinia plugin, so this is another zero-coverage area.

What needs to happen

• Enumerate which Pinia rules actually fire in our codebases. If the answer is "none, ever", this stops being a blocker and becomes a deletion.
• If some do fire, judge whether the failure mode they prevent is worth an ESLint dependency on its own.

Why this is likely the cheapest blocker to clear

Pinia store misuse tends to fail loudly at runtime or in tests, unlike a11y issues. Measuring real hit rate first is worth more than seeking parity.