feat: integrate prettier and enforce code formatting

[Rahul-R79]

Closes #191

This PR integrates Prettier into the project to handle code formatting, separating stylistic concerns from code quality checks (ESLint). It also adds a mandatory formatting check in the CI pipeline.

Changes

• Added Dependencies: prettier and eslint-config-prettier.
• Added Configuration: Created .prettierrc with modern defaults (2-space indentation, single quotes, no trailing whitespace).
• Updated Scripts: Added npm run format (write) and npm run format:check (verify) to package.json.
• Updated ESLint: Modified .eslintrc.yml to extend prettier, disabling conflicting formatting rules.
• Updated CI: Added npm run format:check step to .github/workflows/build.yml to fail builds on formatting errors.
• Reformatted Codebase: Applied Prettier formatting to all source files (~133 files changed).

Flags

• Large Diff: This PR touches ~130 files due to whitespace/indentation changes (moving from 4 spaces to 2 spaces).
• History Mitigation: After merging, we should add the commit hash to .git-blame-ignore-revs (in a follow-up PR) to preserve git blame usability.

Screenshots or Video

N/A (Formatting changes only)

Related Issues

• Issue feat: Integrate Prettier for Code Formatting and CI Check #191

Author Checklist

• Ensure you provide a DCO sign-off for your commits using the --signoff option of git commit.
• Vital features and changes captured in unit and/or integration tests
• Commits messages follow AP format
• Extend the documentation, if necessary
• Merging to main from fork:feat/add-prettier

[Rahul-R79]

As we discussed in today's call, I've implemented Prettier for consistent formatting and added a CI check to enforce it.

I’ve also run the tests, linting, and Prettier locally, and everything passed successfully with no issues.

Note: To keep git blame clean, I will open a follow-up PR to add this commit hash to .git-blame-ignore-revs after merging, effectively hiding this massive reformatting from history.

Please review when you get some time @mttrbrts @dselman !

[coveralls]

coverage: 98.363%. remained the same
when pulling a11a36e on Rahul-R79:feat/add-prettier
into 461d268 on accordproject:main.

[Rahul-R79]

@ekarademir @mttrbrts @dselman please take a look at this when you have some time. Thank you.!

[Copilot]

Pull request overview

Integrates Prettier-based formatting into the repo, aiming to separate formatting concerns from ESLint and (per PR description) enforce formatting in CI.

Changes:

• Add Prettier + eslint-config-prettier, and introduce format / format:check npm scripts.
• Add Prettier configuration and ignore rules.
• Update ESLint config to extend prettier and remove formatting-related rules; add VS Code workspace settings to default to Prettier.

Reviewed changes

Copilot reviewed 5 out of 6 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
package.json	Adds Prettier scripts and devDependencies; reformats JSON.
package-lock.json	Locks new Prettier and eslint-config-prettier dependencies.
.vscode/settings.json	Configures VS Code to format on save with Prettier and run ESLint fixes.
.prettierrc	Introduces Prettier configuration (tab width, quotes, etc.).
.prettierignore	Excludes build/artifact directories from Prettier runs.
.eslintrc.yml	Extends prettier and removes ESLint formatting rules.

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[Copilot]

The PR description says CI enforces formatting via npm run format:check, but the current workflow(s) don't appear to run that command. To make formatting mandatory (and avoid style regressions now that ESLint formatting rules were removed), add a CI step that runs npm run format:check (typically right after npm ci).

[Rahul-R79]

My intention is not to add npm run format:check to the CI pipeline right now. Copilot is suggesting adding it to the pipeline, but if I do that, I need to format the entire codebase, which would result in a large diff that's hard to review — that's the feedback I received from the weekly call's. So I changed the plan accordingly.

Instead, I implemented a VS Code extension setting so that contributors' files are automatically formatted on save. My intention in adding "format:check": "prettier --check ." is to help contributors manually run the format check locally if they don't have the Prettier extension installed. This way, we can gradually improve the codebase over time.

so can i ignore the suggestion @mttrbrts @sanketshevkar

[mttrbrts]

Let's keep the 4 space indenting to remain consistent with other projects in this org, e.g. https://github.com/accordproject/concerto/blob/main/.eslintrc.yml