package json main field extension order

[dylan-conway]

fixes #3659

[github-actions]

❌ @dylan-conway 1 files with test failures on linux-x64:

• test/js/web/fetch/fetch-leak.test.js

View test output

^{#d32f63ce1be0a32733417c1293b6b0eee97f8362}

[github-actions]

❌ @dylan-conway 1 files with test failures on linux-x64-baseline:

• test/js/web/fetch/fetch-leak.test.js

View test output

^{#d32f63ce1be0a32733417c1293b6b0eee97f8362}

[github-actions]

❌ @dylan-conway 5 files with test failures on bun-darwin-aarch64:

• test/js/bun/spawn/spawn-streaming-stdout.test.ts
• test/js/bun/spawn/spawn.test.ts
• test/js/bun/test/test-test.test.ts
• test/js/web/fetch/fetch-leak.test.js
• test/js/web/fetch/fetch_headers.test.js

View test output

^{#d32f63ce1be0a32733417c1293b6b0eee97f8362}

[github-actions]

❌ @dylan-conway 6 files with test failures on bun-darwin-x64-baseline:

• test/js/bun/spawn/spawn-streaming-stdin.test.ts
• test/js/bun/spawn/spawn-streaming-stdout.test.ts
• test/js/bun/spawn/spawn.test.ts
• test/js/bun/sqlite/sqlite.test.js
• test/js/third_party/webpack/webpack.test.ts
• test/js/web/timers/setTimeout.test.js

View test output

^{#d32f63ce1be0a32733417c1293b6b0eee97f8362}

[capaj]

lovely, this should fix it for good. I've been using this exact resolution order in vitest without any issue at least a year now on multiple projects.