Remove GitHub-specific files and references

- Remove GitHub Actions CI workflow
- Update CONTRIBUTING.md to be forge-agnostic (Gitea/GitLab/etc)
- This is a Git project, not GitHub-specific

.github/workflows/build.yml

@@ -1,44 +0,0 @@
-name: Build and Test
-
-on:
-  push:
-    branches: [ main, master ]
-  pull_request:
-    branches: [ main, master ]
-
-jobs:
-  build:
-    # ubuntu-latest is just the GitHub Actions runner OS - PassAGE works on any Linux/Unix distro
-    runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        go-version: ['1.21', '1.22']
-
-    steps:
-    - uses: actions/checkout@v4
-
-    - name: Set up Go
-      uses: actions/setup-go@v5
-      with:
-        go-version: ${{ matrix.go-version }}
-
-    - name: Verify dependencies
-      run: go mod verify
-
-    - name: Download dependencies
-      run: go mod download
-
-    - name: Build
-      run: go build -v -o passage .
-
-    - name: Test
-      run: go test -v ./...
-
-    - name: Build release version
-      run: go build -trimpath -ldflags "-s -w" -o passage-release .
-
-    - name: Check manpage builds
-      run: |
-        sudo apt-get update
-        sudo apt-get install -y pandoc
-        make man

CONTRIBUTING.md

@@ -4,11 +4,11 @@ Thank you for your interest in contributing to PassAGE!
 
 ## Getting Started
 
-1. **Fork the repository**
-2. **Clone your fork** locally
+1. **Fork the repository** (if using a forge like Gitea)
+2. **Clone the repository** locally
 3. **Create a branch** for your changes
 4. **Make your changes** and test them
-5. **Submit a pull request**
+5. **Submit a merge request** or push your changes
 
 ## Development Setup