docs: add naming convention rule to CONTRIBUTING.md

Prefer PyPI package name as display name so developers can copy it
directly to pip install. Fall back to GitHub repo name if not on PyPI.
Also update examples to use lowercase PyPI names.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

CONTRIBUTING.md

@@ -18,7 +18,7 @@ Your submission must meet **ONE** of the following criteria:
 ### 1. Industry Standard
 
 - The go-to tool that almost everyone uses for a specific use case
-- Examples: Requests, Flask, Pandas, NumPy
+- Examples: requests, flask, pandas, numpy
 - Limit: 1-3 tools per category
 
 ### 2. Rising Star
@@ -26,7 +26,7 @@ Your submission must meet **ONE** of the following criteria:
 - Rapid growth: 5,000+ GitHub stars in less than 2 years
 - Significant community buzz and adoption
 - Solving problems in new or better ways
-- Examples: FastAPI, Ruff, uv
+- Examples: fastapi, ruff, uv
 
 ### 3. Hidden Gem
 
@@ -41,10 +41,14 @@ Your submission must meet **ONE** of the following criteria:
 
 **Use GitHub repository URLs** whenever possible. Projects linked to a GitHub repo are ranked higher on [awesome-python.com](https://awesome-python.com/).
 
+### Naming Convention
+
+Use the **PyPI package name** as the display name so developers can copy it directly to `pip install`. Check the canonical name at `https://pypi.org/pypi/{package}/json`. If the project is not on PyPI, use the GitHub repository name instead.
+
 ### Standard Entry
 
 ```markdown
-- [project-name](https://github.com/owner/repo) - Description ending with period.
+- [pypi-name](https://github.com/owner/repo) - Description ending with period.
 ```
 
 ### Standard Library Module