feat: add nightly workflow for automated release management

.github/workflows/nightly.yml

@@ -0,0 +1,64 @@
+name: nightly
+permissions:
+  contents: write
+on:
+  schedule:
+    - cron: '0 10 * * *'
+  push:
+    paths:
+      - '.github/workflows/nightly.yml'
+jobs:
+  init:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/github-script@v7 
+      with: 
+        script: |
+          const releases = await github.rest.repos.listReleases({
+            owner: context.repo.owner,
+            repo: context.repo.repo,
+          });
+          for (const release of releases.data) {
+            if (release.tag_name === 'nightly') {
+              await github.rest.repos.deleteRelease({
+                owner: context.repo.owner,
+                repo: context.repo.repo,
+                release_id: release.id,
+              });
+            }
+          }
+          try {
+            await github.rest.git.deleteRef({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              ref: `tags/nightly`,
+            });
+          } catch (error) {}
+  nightly:
+    needs: init
+    strategy:
+      matrix:
+        platform:
+          - runner: ubuntu-latest
+            os: ubuntu-latest
+          - runner: windows-latest
+            os: windows-latest
+          - runner: macos-latest
+            os: macos-latest
+    runs-on: ${{ matrix.platform.runner }}
+    steps:
+    - uses: actions/checkout@v4
+    - uses: actboy168/action-zip@main
+      id: zip
+      with:
+        name: swi-prolog-docs-${{ matrix.platform.runner }}-${{ github.sha }}
+        path: |
+          src/*
+          README.rst
+          COPYING
+    - uses: softprops/action-gh-release@v1
+      with:
+        name: nightly
+        tag_name: nightly
+        fail_on_unmatched_files: true
+        files: ${{  steps.zip.outputs.output }}