Sync editor settings

Ensure Biome, Zed, and VS Code all use consistent formatting and linting settings.

Tasks

• Configure Zed to use Biome for formatting
• Configure VS Code to use Biome extension
• Add .vscode/settings.json with Biome as default formatter
• Add .zed/settings.json with Biome configuration
• Ensure indent style (tabs) and width (4) match across all tools
• Test formatting consistency across editors