forgejo-cI: clean-up previews based on SHA rather than PR metadata

.forgejo/workflows/cleanup.yaml

@@ -10,8 +10,7 @@ jobs:
     steps:
       - name: Environment setup
         run: |
-          apk add git nodejs jq coreutils curl tree
-          echo "GITHUB_PR_NAME=$(curl -Ls ${{ github.server_url }}/api/v1/repos/${{ github.repository }}/pulls/${{ github.ref_name }} | jq .title | tr ' ' '-' | tr -d ':' | tr -d '"' | tr '[:upper:]' '[:lower:]' )" >> $GITHUB_ENV
+          apk add git nodejs jq coreutils curl tree gawk grep
       - name: Public repo pull
         uses: actions/checkout@v4
         with:
@@ -20,6 +19,7 @@ jobs:
           ref: public
       - name: Render website
         run: |
+          echo "GITHUB_PR_NAME=$(grep -l ${{ github.sha }} previews/*/git_sha.txt | awk -F '/' '{print $2}')" >> $GITHUB_ENV
           rm -rf previews/$GITHUB_PR_NAME || true
           cd previews
           tree -d -H '.' -L 1 --noreport --charset utf-8 -T "Versions" -o index.html

.forgejo/workflows/preview.yaml

@@ -40,6 +40,7 @@ jobs:
           git log -1 --pretty=%B > commit.txt
           cd public
           date > previews/$GITHUB_PR_NAME/generated.txt
+          echo ${{ github.sha }} > previews/$GITHUB_PR_NAME/git_sha.txt
           # Note: the following account information will not work on GHES
           git config user.name "forgejo-actions[bot]"
           git config user.email "dev@ayakael.net"