chore: upgrade to Biome v2

[3w36zj6]

https://biomejs.dev/guides/upgrade-to-biome-v2/

[Copilot]

Pull Request Overview

This PR upgrades the project from Biome v1.9.4 to v2.0.6, implementing the configuration changes and code formatting updates required for the new version.

• Updates Biome dependency and configuration files
• Applies automated code formatting and import organization
• Prefixes unused parameters with underscore to follow linting rules

Reviewed Changes

Copilot reviewed 19 out of 20 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
website/package.json	Updates Biome dependency from 1.9.4 to 2.0.6
website/biome.json	Removes old v1 configuration file
website/biome.jsonc	Adds new v2 configuration with enhanced linting rules
website/vite.config.ts	Combines import statements for better organization
website/src/translation/ja-JP.tsx	Replaces React fragments with explicit Fragment imports
website/src/translation/en-US.tsx	Replaces React fragments with explicit Fragment imports
website/src/translation/index.tsx	Reorders export statement alphabetically
website/src/index.tsx	Moves import statement and prefixes unused parameter
website/src/globals.css	Reformats font-family property for better readability
website/src/utils/flattenDocs.test.ts	Prefixes unused variable with underscore
Multiple component files	Reorders imports and prefixes unused parameters with underscores

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