docs: update v1 options examples

[ishaanlabs-gg]

What's Changing and Why

Updates Jimp v1 documentation examples that still showed pre-v1 positional method arguments:

• flip(true, false) now uses flip({ horizontal: true, vertical: false }).
• resize(256, 100) and resize(256, 256) examples now use { w, h } options objects.

This matches the current v1 API and addresses the stale docs reported in #1389.

What else might be affected

Documentation/example output only. Runtime code is unchanged.

Tasks

• Add tests
• Update Documentation
• Update jimp.d.ts
• Add SemVer Label

Validation:

• git diff --check
• npx --yes prettier@3.3.3 --check plugins/plugin-flip/src/index.ts packages/jimp/src/index.ts packages/jimp/README.md

Closes #1389