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/recover.py

@@ -0,0 +1,71 @@
+"""FLR session helpers."""
+
+from __future__ import annotations
+
+import asyncio
+from typing import Any
+
+from zerto_rewind_mcp.client import ZertoClient, ZertoError
+from zerto_rewind_mcp.util import pick
+
+
+def session_id_from(payload: Any) -> str:
+    if payload is None:
+        raise ZertoError("FLR start returned empty body")
+    if isinstance(payload, str):
+        return payload.strip().strip('"')
+    if isinstance(payload, dict):
+        value = pick(
+            payload,
+            "sessionId",
+            "SessionId",
+            "flrSessionIdentifier",
+            "identifier",
+            "Identifier",
+            "id",
+            "Id",
+        )
+        if value:
+            return str(value)
+    raise ZertoError(f"Could not read FLR session id from {payload!r}")
+
+
+def download_token_from(payload: Any) -> str:
+    if isinstance(payload, str):
+        return payload.strip().strip('"')
+    if isinstance(payload, dict):
+        value = pick(payload, "token", "Token", "downloadToken", "DownloadToken")
+        if value:
+            return str(value)
+    raise ZertoError(f"Could not read FLR download token from {payload!r}")
+
+
+async def wait_flr_ready(
+    client: ZertoClient,
+    session_id: str,
+    *,
+    timeout_s: float = 180.0,
+    interval_s: float = 3.0,
+) -> dict[str, Any]:
+    deadline = asyncio.get_event_loop().time() + timeout_s
+    last: Any = None
+    while asyncio.get_event_loop().time() < deadline:
+        last = await client.get_flr(session_id)
+        status = ""
+        if isinstance(last, dict):
+            status = str(pick(last, "Status", "status", "state", "State") or "")
+        if status.lower() in {"ready", "mounted", "available"}:
+            return last if isinstance(last, dict) else {"status": status}
+        if "mountinprogress" in status.lower() or "inprogress" in status.lower():
+            await asyncio.sleep(interval_s)
+            continue
+        if status.lower() in {"failed", "error"}:
+            raise ZertoError(f"FLR session {session_id} failed: {last}")
+        # some appliances omit status once mounted
+        if isinstance(last, dict) and not status:
+            return last
+        await asyncio.sleep(interval_s)
+    raise ZertoError(
+        f"FLR session {session_id} not ready within {timeout_s:.0f}s (last={last!r}). "
+        "Retry browse after a minute, or check EJC is not running and no clone/test is active."
+    )