Improve contribution guidelines

CONTRIBUTING.md

@@ -1,17 +1,75 @@
-# Contribution Guidelines
+# Contributing
 
-Unfortunately, not every user script can be considered. The aim of the list is to provide a concise list of noteworthy user scripts and that fill a gap.
+Awesome Userscripts is a curated list, so not every submission will be accepted. Entries should be useful, maintained, safe to install, and meaningfully different from scripts already listed.
 
+## Before submitting
 
-Furthermore, please ensure your pull request follows the following guidelines:
+- Search the README, open issues, and open pull requests for duplicates.
+- Confirm the userscript still works with a current browser and userscript manager.
+- Use a stable, direct installation URL. Do not link to shortened or temporary URLs.
+- Check that documentation and bug-report links are public and current.
+- Submit one userscript per pull request. Category-wide improvements may be grouped when they form one focused change.
 
-* Please search previous suggestions before making a new one, as yours may be a duplicate.
-* Please make an individual pull request for each suggestion.
-* Entries should be sorted in ascending alphabetical order, i.e. a to z.
-* New categories, or improvements to the existing categorization are welcome.
-* Keep descriptions short, simple and unbiased. 
-* End all descriptions with a full stop/period.
-* Check your spelling and grammar.
-* Make sure your text editor is set to remove trailing whitespace.
+## Entry requirements
 
-Thank you for your suggestions!
+Each submission should include:
+
+- Script name and a short, factual description ending with a period.
+- Project, documentation, or catalogue page describing the script.
+- Direct userscript installation link.
+- Public bug tracker or support page when available.
+- Screenshot or demo image when it helps explain visible behavior.
+- Browser and userscript-manager combinations used for testing.
+
+Descriptions should explain what the script does without promotional language, download counts, or unsupported claims. New entries must be placed alphabetically within the best matching category.
+
+## Entry format
+
+Match surrounding README markup. Use these link labels consistently:
+
+- 💾 `Install` for a direct userscript installation link.
+- 📖 `Readme` for documentation.
+- 📢 `Discuss` for a discussion or community page.
+- 🐛 `Report bug` for an issue tracker.
+
+Omit unavailable optional links instead of changing a label's meaning.
+
+```html
+<details> <!-- Script Name -->
+    <summary><a href="PROJECT_URL">Script Name</a> - Short, factual description.</summary><br>
+    <blockquote>
+        <a href="PROJECT_URL">
+            <img width=511 src="SCREENSHOT_URL"></a>
+    </blockquote>
+    <blockquote>
+        💾 <a href="INSTALL_URL">
+            Install</a> /
+        📖 <a href="README_URL">
+            Readme</a> /
+        📢 <a href="DISCUSSION_URL">
+            Discuss</a> /
+        🐛 <a href="ISSUES_URL">
+            Report bug</a>
+    </blockquote>
+</details>
+```
+
+## Validate changes
+
+Use Node.js 24, matching CI:
+
+```sh
+npm ci --ignore-scripts
+npm run lint
+```
+
+Also open every added or changed link and verify that the install link serves the intended userscript.
+
+## Pull request checklist
+
+- Change is focused on one script or one related improvement.
+- Entry is alphabetized and follows surrounding markup.
+- Description is concise, factual, and ends with a period.
+- Install, documentation, image, and support links work.
+- Script was tested, with browser and userscript manager named in the pull request.
+- `npm run lint` passes.