fix: restore tree dropped by 6d224861; land stem95su gdrive-sync (10m) [ci skip]

6d224861 came from a --no-checkout worktree whose empty index made the
commit drop every file except two. This restores 05b50d2b's full tree and
correctly adds stacks/stem95su/gdrive-sync.tf + the service-catalog stem95su
entry. Forward-only (parent=6d224861, no force-push); [ci skip] since the
live infra was never applied from the broken commit.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.github/workflows/build-diun.yml

@@ -0,0 +1,28 @@
+name: Build Custom DIUN Image
+
+on:
+  push:
+    branches: [master]
+    paths:
+      - 'stacks/diun/Dockerfile'
+  workflow_dispatch:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: docker/setup-buildx-action@v3
+
+      - uses: docker/login-action@v3
+        with:
+          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+
+      - uses: docker/build-push-action@v6
+        with:
+          context: stacks/diun
+          platforms: linux/amd64
+          push: true
+          tags: viktorbarzin/diun:latest