Temporary debug workflow to inspect CI_SSH_KEY shape

.gitea/workflows/debug-key.yaml

@@ -0,0 +1,18 @@
+name: debug-key
+
+on:
+  workflow_dispatch:
+
+jobs:
+  debug:
+    runs-on: deploy
+    steps:
+      - name: Inspect CI_SSH_KEY shape (no secret content exposed)
+        env:
+          CI_SSH_KEY: ${{ secrets.CI_SSH_KEY }}
+        run: |
+          echo "line count: $(printf '%s' "$CI_SSH_KEY" | wc -l)"
+          echo "char count: $(printf '%s' "$CI_SSH_KEY" | wc -c)"
+          printf '%s' "$CI_SSH_KEY" | head -c 30
+          echo
+          printf '%s' "$CI_SSH_KEY" | tail -c 30