Improve build configuration and add Prettier formatting

[isc-klu]

This PR adjusts various configuration files to improve long-term maintainability of the codebase:

• Simplifies tsconfig.json and eslint.config.mjs by removing configuration options that are no longer necessary.
• Adds Prettier for consistent code style checking and formatting, aligning with the sibling codebase (vscode-objectscript).

Notable changes

The majority of file changes are automated Prettier formatting and are not individually noteworthy. The meaningful changes are:

File(s)	Change
eslint.config.mjs, tsconfig.json	Simplified by removing unnecessary configuration
.gitignore	Added tsconfig.tsbuildinfo (TypeScript incremental build artifact)
.prettierignore	Created to limit Prettier to TypeScript files only
package.json	Added prettier as a devDependency with its configuration; added lint and lint-fix scripts that utilize Prettier for style checking and fixing; removed globals (unused devDependency)
package-lock.json	Regenerated by npm to reflect the updated package.json
client/package-lock.json, server/package-lock.json	Version numbers updated by npm to match their corresponding package.json

[isc-bsaviano]

Thanks for doing this! You should add the new .prettierignore file to .vscodeignore.

[isc-bsaviano]

@isc-klu This is ready to go once you update .vscodeignore

[isc-klu]

@isc-klu This is ready to go once you update .vscodeignore

Added. Thanks for the reminder!