docs: add CONTRIBUTING guide

[hasansezertasan]

Description

Adds a root CONTRIBUTING.rst — a contributor onboarding guide covering environment setup, the contribution workflow, code guidelines, testing, and documentation. Linked from the README's Local development section.

Adapted from #16 with these changes to match this repo's current state:

• PDM → uv. Litestarification #16's guide was PDM-based; this uses uv and the existing uv-based Makefile targets (make install, make lint, make test, make coverage, make docs-serve, …).
• Cleaned up RST. Litestarification #16's .jinja had broken/over-indented directives from copier rendering; this is hand-written, valid RST.
• Dropped the release section. It depended on tools/prepare_release.py, which does not exist in this repo (it was introduced in Litestarification #16). Release steps already live in the README.
• Removed copier placeholders ({{ project_name }}, {{ module_name }}) → project-template / project_template.

The file is .rst to stay consistent with the Sphinx docs — and make docs-serve already watches CONTRIBUTING.rst.

Validated with sphinx-lint → No problems found.

Closes

• Closes docs: add CONTRIBUTING guide #23

Summary by Sourcery

Add a root-level CONTRIBUTING guide and reference it from the README to support contributor onboarding.

Documentation:

• Introduce CONTRIBUTING.rst as a comprehensive contributor guide covering setup, workflow, code, testing, and docs.
• Link the new CONTRIBUTING guide from the README local development section for discoverability.

[sourcery-ai]

Reviewer's guide (collapsed on small PRs)

Reviewer's Guide

Adds a root CONTRIBUTING.rst contributor guide and links it from the README’s local development section, aligning contributor workflow and tooling docs with the project’s current uv + Makefile setup and Sphinx documentation format.

Flow diagram for contributor documentation navigation

flowchart TD
    README[README.md Local_development_section]
    CONTRIBUTING[CONTRIBUTING.rst Contributor_guide]
    Sphinx[Sphinx_docs]

    README --> CONTRIBUTING
    CONTRIBUTING --> Sphinx

Loading

File-Level Changes

Change	Details	Files
Introduce a Sphinx-friendly CONTRIBUTING guide describing contributor workflow and tooling, and reference it from the README.	Add CONTRIBUTING.rst at the repo root, written in valid reStructuredText and structured as a contributor onboarding guide (environment setup, workflow, code style, testing, documentation). Align contribution instructions with the existing uv-based Makefile targets (e.g., make install, make lint, make test, make coverage, make docs-serve) instead of PDM commands. Remove release-process instructions that depended on tools/prepare_release.py and rely on the existing README release section instead. Replace prior copier template placeholders with concrete project-template / project_template names to match this repository state. Update README.md local development section to link to CONTRIBUTING.rst as the canonical contribution guide.	CONTRIBUTING.rst README.md

Assessment against linked issues

Issue	Objective	Addressed	Explanation
#23	Add a CONTRIBUTING file covering uv setup, running tests, pre-commit, conventional commits/branches/PR titles, and docs build.	✅
#23	Link the CONTRIBUTING guide from README.md and the issue/PR templates.	❌	The PR links CONTRIBUTING.rst from README.md but does not modify or link it from the issue or PR templates.
#23	Reference the org-wide Code of Conduct in the CONTRIBUTING guide.	❌	The diff and PR description do not show any addition of a link or reference to the org-wide Code of Conduct, so it appears not to be included.

---

Tips and commands

Interacting with Sourcery

• Trigger a new review: Comment @sourcery-ai review on the pull request.
• Continue discussions: Reply directly to Sourcery's review comments.
• Generate a GitHub issue from a review comment: Ask Sourcery to create an
  issue from a review comment by replying to it. You can also reply to a
  review comment with @sourcery-ai issue to create an issue from it.
• Generate a pull request title: Write @sourcery-ai anywhere in the pull
  request title to generate a title at any time. You can also comment
  @sourcery-ai title on the pull request to (re-)generate the title at any time.
• Generate a pull request summary: Write @sourcery-ai summary anywhere in
  the pull request body to generate a PR summary at any time exactly where you
  want it. You can also comment @sourcery-ai summary on the pull request to
  (re-)generate the summary at any time.
• Generate reviewer's guide: Comment @sourcery-ai guide on the pull
  request to (re-)generate the reviewer's guide at any time.
• Resolve all Sourcery comments: Comment @sourcery-ai resolve on the
  pull request to resolve all Sourcery comments. Useful if you've already
  addressed all the comments and don't want to see them anymore.
• Dismiss all Sourcery reviews: Comment @sourcery-ai dismiss on the pull
  request to dismiss all existing Sourcery reviews. Especially useful if you
  want to start fresh with a new review - don't forget to comment
  @sourcery-ai review to trigger a new review!

Customizing Your Experience

Access your dashboard to:

• Enable or disable review features such as the Sourcery-generated pull request
  summary, the reviewer's guide, and others.
• Change the review language.
• Add, remove or edit custom review instructions.
• Adjust other review settings.

Getting Help

• Contact our support team for questions or feedback.
• Visit our documentation for detailed guides and information.
• Keep in touch with the Sourcery team by following us on X/Twitter, LinkedIn or GitHub.

[sourcery-ai]

Hey - I've reviewed your changes and they look great!

---

Sourcery is free for open source - if you like our reviews please consider sharing them ✨

• X
• Mastodon
• LinkedIn
• Facebook

_{Help me be more useful! Please click 👍 or 👎 on each comment and I'll use the feedback to improve your reviews.}