chore: replace @mizdra/oxfmt-config with local .oxfmtrc.json

[mizdra]

Summary

• Add .oxfmtrc.json to the repository root with the same settings as @mizdra/oxfmt-config
• Remove @mizdra/oxfmt-config dependency
• Update lint:oxfmt script to use auto-detected config (remove -c option)

The VS Code oxc extension did not recognize ./node_modules/@mizdra/oxfmt-config/.oxfmtrc.json, causing a diff between formatOnSave and npm run lint:oxfmt. Placing .oxfmtrc.json directly in the repository root resolves this issue.

Test plan

• npm run lint:oxfmt passes successfully

🤖 Generated with Claude Code

[changeset-bot]

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Latest commit: 2f5c745

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