refactor: fix unicorn/no-new-array and enable tightened lint rules (stage 3) #71

What

Part of the v2 standardization (stage 3, after stage 1/#67-68 and stage 2/#69-70):

• Fix the 10 pre-existing unicorn/no-new-array violations in packages/hdrify/src/exr/pizHuffman.ts and b44Codec.test.ts (deferred from stage 1, see chore: standardize CI/tooling to v2 canonical (stage 1) #68) using Array.from({ length }) or equivalent.
• Flip unicorn/no-new-array to "error" in .oxlintrc.json so it matches canonical byte-for-byte (already true for typescript/no-explicit-any and eslint/no-unused-private-class-members).

Acceptance criteria

• .oxlintrc.json byte-identical to canonical (except ignorePatterns)
• pnpm lint, pnpm build, pnpm tsc, pnpm test all pass
• CI green