feat(poc): rewind MCP, skill, and recover-ladder docs

Initial PoC: find_protection, tagged checkpoints, FLR, mutating catalog.
Lab 10.9 status enums (0=Initializing, 1=MeetingSLA). Credentials stay in gitignored config.json.

src/zerto_rewind_mcp/util.py

@@ -0,0 +1,16 @@
+"""JSON key access. Zerto mixes PascalCase and camelCase across versions."""
+
+from __future__ import annotations
+
+from typing import Any
+
+
+def pick(row: dict[str, Any], *names: str) -> Any:
+    for name in names:
+        if name in row and row[name] is not None:
+            return row[name]
+    lower = {k.lower(): v for k, v in row.items()}
+    for name in names:
+        if name.lower() in lower and lower[name.lower()] is not None:
+            return lower[name.lower()]
+    return None