Migrate to oxlint

[logaretm]

Replace ESLint with oxlint across the monorepo for dramatically faster linting.

Benchmarks

Per-package linting is 77x–181x faster (seconds → milliseconds). Headline numbers:

• yarn lint:lerna: 133s → 11s (12x faster) — Lerna overhead eats most of the raw gains
• CI lint job: 5m 58s → 2m 32s (2.4x faster) — bottlenecked by the types build step, not linting
• Individual packages: core 9.6s → 53ms (181x), browser 6.8 → 55ms (124x), nextjs 10.9s → 79ms (138x)

Scope

• Replace all .eslintrc.* files with .oxlintrc.json configs
• Update lint scripts from eslint . to oxlint .
• Migrate all existing rules or document gaps
• Keep eslint-config-sdk and eslint-plugin-sdk packages (published for external SDK users)
• Keep ESLint in e2e test apps (they simulate real user setups)

Known gaps

• Import sorting (simple-import-sort) — can use oxfmt's built-in import sorting instead
• Some TypeScript-specific rules (member-ordering, naming-convention)
• 4 custom Sentry lint rules — can be ported via oxlint JS plugins later

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Tracking PR: #19134

[linear]

JS-1660