fix(workflows): normalize default branch to main across CI/release workflows and docs; update package metadata; clean .gitignore and fix readme license link

.gitea/workflows/README.md

@@ -6,7 +6,7 @@ This directory contains Gitea Actions workflows for automated CI/CD of the SZCI
 
 ### 1. CI (`ci.yml`)
 
-**Trigger:** Push to `master` branch or pull requests
+**Trigger:** Push to `main` branch or pull requests
 
 **Purpose:** Continuous integration checks on every push
 
@@ -87,7 +87,7 @@ To create a new release:
 3. **Create and push tag:**
    ```bash
    git tag v6.0.1
-   git push origin master
+   git push origin main
    git push origin v6.0.1
    ```