Enable default oxlint correctness rules

[kmcginnes]

Description

Fixes 39 lint violations and flips the oxlint correctness category from "off" to "error". This means new correctness rules will be automatically enabled on oxlint upgrades.

• Fix no-unused-expressions (13) — convert ternary/&& statements to if/else
• Fix no-useless-fallback-in-spread (13) — remove unnecessary || {} from spreads
• Fix no-misused-spread (6) — fix unsafe spreads of arrays/iterables in objects; add disable comments for intentional MouseEvent/Error property extraction
• Fix no-meaningless-void-operator (4) — remove void from already-void calls
• Fix no-useless-length-check (2) — remove redundant .length > 0 before .some()
• Fix no-useless-default-assignment (1) — remove default on non-nullish property
• Simplify .oxlintrc.json — remove ~60 individual rule entries now redundant with the category default

Validation

• pnpm checks passes (119 rules, 0 errors)
• pnpm test passes (153 files, 1660 tests)

Related Issues

• Resolves Enable default oxlint correctness rules #1747

Check List

• I confirm that my contribution is made under the terms of the Apache 2.0 license.
• I have verified pnpm checks passes with no errors.
• I have verified pnpm test passes with no failures.
• I have covered new added functionality with unit tests if necessary.
• I have updated documentation if necessary.