(release) Harden SSH key edit and delete flow

Make SSH credential management more explicit by adding an edit action in the
key overview and requiring name confirmation before deletion. Keep deletion
blocked while a key is still selected by hosts or global config, and cover
rename, delete confirmation, and in-use protection in view tests.

Refs #20
Refs #8

src/pobsync_backend/views.py

@@ -239,6 +239,9 @@ def delete_ssh_credential(request, credential_id: int):
     if credential.hosts.exists() or credential.global_configs.exists():
         messages.error(request, f"SSH key {credential.name} is still in use and cannot be deleted.")
         return redirect("edit_ssh_credential", credential_id=credential.id)
+    if request.POST.get("confirm_name", "").strip() != credential.name:
+        messages.error(request, f"Type {credential.name} to confirm SSH key deletion.")
+        return redirect("edit_ssh_credential", credential_id=credential.id)
 
     name = credential.name
     try: