* 📦 build: upgrade to Mantine 9, React 19, TypeScript 6, and modernize tooling

[gfazioli]

• Upgrade @mantine/core and @mantine/hooks to 9.0.0 across root and docs workspaces
• Migrate from ESLint to oxlint with typed config (oxlint.config.ts) and remove eslint.config.mjs and tsconfig.eslint.json
• Replace Prettier with oxfmt for formatting (.prettierrc.mjs → .oxfmtrc.json) with matching import-order and ignore rules
• Bump Yarn from 4.12.0 to 4.13.0 (.yarn/releases and .yarnrc.yml)
• Upgrade TypeScript to 6.0.2, React to 19.2.4, and Storybook to v10 (@storybook/react-vite, @storybook/addon-themes)
• Update CI workflow (pull_request.yml) and Storybook config (main.ts, preview.tsx) for new tooling
• Align SelectStepper component and tests with Mantine 9 API and updated @mantine-tests/core
• Update README to reflect Mantine 9.x requirement and docs/package.json dependencies
• Refresh CLAUDE.md with current commands (oxfmt:write, oxlint) and architecture notes
• Regenerate yarn.lock to resolve all updated dependency versions

[Copilot]

Pull request overview

This PR upgrades the component library and docs workspace to Mantine 9 / React 19 / TypeScript 6, while modernizing the repo’s tooling by replacing ESLint+Prettier with oxlint+oxfmt and updating Storybook/CI configuration accordingly.

Changes:

• Upgrade core dependencies (Mantine 9, React 19, TypeScript 6) and align SelectStepper implementation/tests with the new Mantine APIs.
• Replace ESLint/Prettier with oxlint/oxfmt and update scripts/configuration.
• Update Storybook and CI workflow to reflect the new toolchain and Node version sourcing.

Reviewed changes

Copilot reviewed 17 out of 21 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
tsconfig.json	Switch module resolution to bundler for newer TS/tooling expectations.
tsconfig.eslint.json	Removed (ESLint no longer used).
tsconfig.build.json	Narrow build compilation scope and adjust declaration build options.
README.md	Document Mantine 9.x / React 19 requirement.
package/src/SelectStepper.tsx	Mantine 9 adjustments and internal logic tweaks; ref forwarding changed.
package/src/SelectStepper.test.tsx	Update expectations around step navigation callback/value behavior.
package.json	Upgrade dependencies and replace prettier/eslint scripts with oxfmt/oxlint.
oxlint.config.ts	Add oxlint configuration (plugins, rules, ignores, overrides).
eslint.config.mjs	Removed (ESLint no longer used).
docs/tsconfig.json	Update target/moduleResolution and reformat for consistency.
docs/package.json	Upgrade docs dependencies to Mantine 9/React 19/TS 6 (one Mantine package left behind).
CLAUDE.md	Refresh developer commands and architecture notes (some commands now mismatch scripts).
.yarnrc.yml	Bump Yarn release reference to 4.13.0.
.storybook/preview.tsx	Update preview setup for Storybook v10 and Mantine color scheme toggling.
.storybook/main.ts	Update Storybook addons/framework config for v10.
.prettierrc.mjs	Removed (Prettier no longer used).
.oxfmtrc.json	Add oxfmt configuration (import order, ignore patterns).
.github/workflows/pull_request.yml	Update workflow name and Node version sourcing via .nvmrc.

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