github: mention all three generated resources

Author: maazm7d

CONTRIBUTING.md

@@ -64,16 +64,24 @@ Thumbnail is **required** for every tool.
 
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-## Stars and READMEs (Auto-Generated)
+## Auto-Generated Metadata
 
-The following files are **automatically managed**:
+The following files are **automatically generated and managed by CI**:
 
 - `metadata/stars.json`  
   - Updated daily at **00:00 UTC**
+  - Contains the latest GitHub star counts for each tool
+
+- `metadata/repo_stats.json`  
+  - Generated by the metadata synchronization workflow
+  - Includes repository statistics such as **forks, issues, pull requests, license, and last update timestamp**
+
 - `metadata/readme/{tool.id}.md`  
-  - Fetched directly from upstream GitHub repositories
+  - README files fetched directly from the upstream GitHub repositories
+  - Badges are stripped and relative links are rewritten
 
-**Do NOT edit these files in pull requests.**
+**Do NOT edit these files in pull requests.**  
+Any manual changes will be overwritten by the CI workflow.
 
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