fix(regression): separate recipe for bad-restore (custom-html-rst-bad)

Having test_backup.py in custom-html-bkp-bad caused both bad-backup and bad-restore
to fail at the backup tier. Create custom-html-rst-bad with its own cc-ci test dir
that has ops.py+test_restore.py but NO test_backup.py, so:
- backup: only generic test_backup_artifact → PASS (snapshot exists)
- restore: pre_restore writes 'mutated', marker stays 'mutated' after restore → FAIL

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/custom-html-rst-bad/ops.py

@@ -0,0 +1,15 @@
+"""custom-html-rst-bad — lifecycle ops for bad-restore RED canary.
+
+NO pre_backup hook: marker never seeded before backup → snapshot has no ci-marker.txt.
+pre_restore writes "mutated". After restore, marker stays "mutated" (not in snapshot) → FAIL.
+"""
+
+from __future__ import annotations
+
+from harness import lifecycle
+
+MARKER_PATH = "/usr/share/nginx/html/ci-marker.txt"
+
+
+def pre_restore(domain: str, meta: dict) -> None:
+    lifecycle.exec_in_app(domain, ["sh", "-c", f"echo mutated > {MARKER_PATH}"])

tests/custom-html-rst-bad/recipe_meta.py

@@ -0,0 +1,3 @@
+# custom-html-rst-bad — regression fixture for bad-restore canary.
+# BACKUP_CAPABLE=True forces the backup tier to run even though the recipe has no backupbot label.
+BACKUP_CAPABLE = True

tests/custom-html-rst-bad/test_restore.py

@@ -0,0 +1,23 @@
+"""custom-html-rst-bad — RESTORE assertion (bad-restore RED canary).
+
+No pre_backup → backup snapshot has no ci-marker.txt. pre_restore writes "mutated".
+After restore: marker is "mutated" (restore can't recover "original" — wasn't backed up) → FAIL.
+"""
+
+import os
+import sys
+
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), "..", "..", "runner"))
+from harness import lifecycle  # noqa: E402
+
+MARKER_PATH = "/usr/share/nginx/html/ci-marker.txt"
+
+
+def test_restore_returns_state(live_app):
+    result = lifecycle.exec_in_app(
+        live_app, ["sh", "-c", f"cat {MARKER_PATH} 2>/dev/null || echo MISSING"]
+    ).strip()
+    assert result == "original", (
+        f"restore did not return the pre-mutation (backed-up) state: got {result!r}. "
+        "Expected 'original'. The backup had no marker, so restore cannot recover it."
+    )

tests/regression/test_canaries.py

@@ -141,13 +141,13 @@ _BAD_BACKUP = {
 
 _BAD_RESTORE = {
     "id": "bad-restore",
-    "recipe": "custom-html-bkp-bad",
-    "src": "recipe-maintainers/custom-html-bkp-bad",
-    # Pin: custom-html-bkp-bad main @ 2026-06-02 (b6fe99de).
-    # No pre_backup hook → marker never seeded before backup → snapshot has no ci-marker.txt.
-    # pre_restore writes "mutated". After restore, marker is MISSING or "mutated" → FAIL → restore=RED.
-    # install+backup PASS; upgrade=skip (no version tags yet).
-    "ref": "b6fe99de41601f9e51bc7ea5b6072f0c3f56cdc3",
+    "recipe": "custom-html-rst-bad",
+    "src": "recipe-maintainers/custom-html-rst-bad",
+    # Pin: custom-html-rst-bad main @ 2026-06-02 (9a73a184).
+    # No pre_backup hook → backup snapshot has no ci-marker.txt.
+    # pre_restore writes "mutated". After restore: marker stays "mutated" → FAIL → restore=RED.
+    # install+backup PASS (no test_backup.py in cc-ci dir); upgrade=skip (no version tags).
+    "ref": "9a73a184e739691bc6a621a5f1e6efc799743c5b",
     "expected_green": False,
     "stages": "install,backup,restore,custom",
     "failing_tier": "restore",