Add CI release and other trigger

.github/workflows/printcss.yml

@@ -2,6 +2,22 @@ name: PrintCSS
 
 on:
   workflow_dispatch:
+    inputs:
+      tag_name:
+        description: "Tag name for release (empty for no release)"
+        required: false
+        default: contiguous
+  push:
+    branches: [ "main" ]
+    tags: ["v[0-9]+.[0-9]+.[0-9]+*"]
+    paths: 
+      - README.md
+      - src/现代C++题目/**
+  pull_request:
+    branches: [ "main" ]
+    paths: 
+      - README.md
+      - src/现代C++题目/**
 
 jobs:
   prepare:
@@ -119,3 +135,60 @@ jobs:
           path: |
             homework_problemtext.pdf
             homework_full.pdf
+  
+  release:
+    runs-on: ubuntu-latest
+    needs: build-printcss
+    permissions:
+      contents: write
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Download artifacts
+      uses: actions/download-artifact@v4
+      with:
+        name: pdf
+        path: artifacts
+
+    - name: Archive and compress
+      run: |
+        find artifacts/ -printf "%P\n" | tar -cvf adocs.tar --no-recursion -C artifacts/ -T -
+        zstd -z -1 adocs.tar -o loser-homework-pdf.tar.zst
+    
+    - if: github.event_name == 'workflow_dispatch'
+      run: echo "TAG_NAME=${{ github.event.inputs.tag_name }}" >> $GITHUB_ENV
+
+    - if: github.event_name == 'schedule'
+      run: echo 'TAG_NAME=contiguous' >> $GITHUB_ENV
+
+    - if: github.event_name == 'push' && startsWith(github.ref, 'refs/tags/')
+      run: |
+        TAG_NAME=${{ github.ref }}
+        echo "TAG_NAME=${TAG_NAME#refs/tags/}" >> $GITHUB_ENV
+        echo "DRAFT=true" >> $GITHUB_ENV
+
+    - if: env.TAG_NAME == 'contiguous'
+      name: Delete previous contiguous
+      env:
+        GH_TOKEN: ${{ github.token }}
+      run: |
+        echo 'PRERELEASE=true' >> $GITHUB_ENV
+        gh release delete contiguous --yes || true
+        git config user.name github-actions
+        git config user.email github-actions@github.com
+        git push origin :contiguous || true
+    - name: Rename release files
+      run: |
+        mv loser-homework-pdf.tar.zst loser-homework-pdf-${{ env.TAG_NAME }}.tar.zst
+    - name: Wait a sec
+      run: sleep 2
+    - name: Release
+      uses: softprops/action-gh-release@v1
+      if: github.event_name != 'pull_request' && env.TAG_NAME != ''
+      with:
+        name: "Docs ${{ env.TAG_NAME }}"
+        prerelease: ${{ env.PRERELEASE != '' }}
+        files: loser-homework-docs-nightly.tar.zst
+        tag_name: ${{ env.TAG_NAME }}
+        draft: ${{ env.DRAFT != '' || null }}
+