Prepare Prettier config

[matux]

Description of the change

Prepares for codebase-wide formatting by modernizing Prettier configuration, matching Olympus/Fuji ruleset and idiosyncrasy.

Changes

• Migrated prettier.config.cjs → prettier.config.js (ESM)
• Upgraded Prettier 3.2.5 → 3.6.2
• Added npm run format and npm run format:check scripts
• Exclude examples directory and fixture sources in test/fixtures to preserve sourcemaps based on the original files.

Related issues

• Linear Project
• Linear Milestone
• SDK-546/migrate-prettier-config-to-modern-esm-format
• SDK-547/add-format-scripts

[Copilot]

Pull Request Overview

Modernizes the Prettier configuration by migrating from CommonJS to ESM format and upgrading to a newer version, along with adding formatting scripts to improve code consistency across the codebase.

• Migrated Prettier config from CommonJS (module.exports) to ESM (export default) format
• Upgraded Prettier from version 3.2.5 to 3.6.2
• Added npm scripts for code formatting and format checking

Reviewed Changes

Copilot reviewed 3 out of 4 changed files in this pull request and generated 1 comment.

File	Description
prettier.config.js	Converted from CommonJS to ESM format and removed trailingComma setting
package.json	Updated Prettier version and added format/format:check npm scripts
eslint.config.mjs	Applied consistent formatting to rule definitions (removing quotes around property names)

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