Convert clients/js to oxlint and oxfmt

[clankmaxxing-clod]

Replaces ESLint + Prettier with oxlint and oxfmt for the clients/js package, following the same migration applied across the other solana-program JS clients (token-group#115, token-metadata, libraries, memo, record, single-pool, stake-pool, token-2022).

Changes

• clients/js/package.json: dropped eslint, @eslint/js, eslint-config-prettier, typescript-eslint, and prettier; added oxlint and oxfmt. Scripts now run the Oxc tools (preserving this package's existing script names):
  • lint → oxlint src
  • lint:fix → oxlint --fix src
  • format → oxfmt --write .
  • format:check → oxfmt --check .
• .oxlintrc.json (new): correctness category as errors, with src/generated ignored (matching the old ESLint ignores).
• .oxfmtrc.json (new): migrated from the workspace's @solana/prettier-config-solana via oxfmt --migrate=prettier (printWidth 120, tabWidth 4, single quotes, arrowParens: avoid); the .prettierignore patterns (node_modules, dist, src/generated/**) were migrated into ignorePatterns.
• Removed eslint.config.mjs and .prettierignore.
• Updated the root pnpm-lock.yaml.

Note on lint coverage

The previous eslint.config.mjs used typescript-eslint's type-aware presets (strictTypeChecked + stylisticTypeChecked with projectService). oxlint does not perform type-aware linting, so the type-checked rules (e.g. no-floating-promises, no-unsafe-*, no-misused-promises, no-unnecessary-condition) are not carried over — this is a best-effort swap that keeps oxlint's correctness category. If preserving those rules matters, oxlint's experimental type-aware linting (tsgolint) could be enabled in a follow-up, or ESLint could be kept solely for type-aware checks.

The shared @solana/prettier-config-solana in the root package.json is intentionally left in place, since codama (generate:clients) still relies on it to format generated output.

Verification

pnpm lint (oxlint, clean; src/generated correctly ignored), pnpm format:check (17 files, no reformatting), and pnpm build (tsc && tsup) all succeed. pnpm test is a no-op (exit 0) in this package. A root pnpm install --frozen-lockfile is consistent with the updated lockfile.

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