Add destination audit wizard with selective deletion

New top-level wizard option (2) lets users inspect and clean up an
existing destination before migration. Queries all SMB shares, NFS
exports, iSCSI objects, datasets, and zvols; displays a structured
inventory report; then offers per-category deletion with escalating
warnings — standard confirm for shares/iSCSI, explicit "DELETE" phrase
required for zvols and datasets to guard against accidental data loss.

Adds to client.py: query_destination_inventory, delete_smb_shares,
delete_nfs_exports, delete_zvols, delete_datasets.
Adds to cli.py: _fmt_bytes, _print_inventory_report, _run_audit_wizard.

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

truenas_migrate/client.py

@@ -382,3 +382,107 @@ async def create_missing_zvols(
     ) as client:
         for name, volsize in zvols.items():
             await create_zvol(client, name, volsize)
+
+
+# ─────────────────────────────────────────────────────────────────────────────
+# Destination inventory
+# ─────────────────────────────────────────────────────────────────────────────
+
+async def query_destination_inventory(client: TrueNASClient) -> dict[str, list]:
+    """
+    Query all current configuration from the destination system.
+    Returns a dict with keys: smb_shares, nfs_exports, datasets, zvols,
+    iscsi_extents, iscsi_initiators, iscsi_portals, iscsi_targets, iscsi_targetextents.
+    Each value is a list (may be empty if the query fails or returns nothing).
+    """
+    result: dict[str, list] = {}
+    for key, method, params in [
+        ("smb_shares",          "sharing.smb.query",        None),
+        ("nfs_exports",         "sharing.nfs.query",        None),
+        ("datasets",            "pool.dataset.query",       [[["type", "=", "FILESYSTEM"]]]),
+        ("zvols",               "pool.dataset.query",       [[["type", "=", "VOLUME"]]]),
+        ("iscsi_extents",       "iscsi.extent.query",       None),
+        ("iscsi_initiators",    "iscsi.initiator.query",    None),
+        ("iscsi_portals",       "iscsi.portal.query",       None),
+        ("iscsi_targets",       "iscsi.target.query",       None),
+        ("iscsi_targetextents", "iscsi.targetextent.query", None),
+    ]:
+        try:
+            result[key] = await client.call(method, params) or []
+        except RuntimeError as exc:
+            log.warning("Could not query %s: %s", key, exc)
+            result[key] = []
+    return result
+
+
+async def delete_smb_shares(
+    client: TrueNASClient, shares: list[dict]
+) -> tuple[int, int]:
+    """Delete SMB shares by ID. Returns (deleted, failed)."""
+    deleted = failed = 0
+    for share in shares:
+        try:
+            await client.call("sharing.smb.delete", [share["id"]])
+            log.info("  Deleted SMB share %r", share.get("name"))
+            deleted += 1
+        except RuntimeError as exc:
+            log.error("  Failed to delete SMB share %r: %s", share.get("name"), exc)
+            failed += 1
+    return deleted, failed
+
+
+async def delete_nfs_exports(
+    client: TrueNASClient, exports: list[dict]
+) -> tuple[int, int]:
+    """Delete NFS exports by ID. Returns (deleted, failed)."""
+    deleted = failed = 0
+    for export in exports:
+        try:
+            await client.call("sharing.nfs.delete", [export["id"]])
+            log.info("  Deleted NFS export %r", export.get("path"))
+            deleted += 1
+        except RuntimeError as exc:
+            log.error("  Failed to delete NFS export %r: %s", export.get("path"), exc)
+            failed += 1
+    return deleted, failed
+
+
+async def delete_zvols(
+    client: TrueNASClient, zvols: list[dict]
+) -> tuple[int, int]:
+    """Delete zvols. Returns (deleted, failed)."""
+    deleted = failed = 0
+    for zvol in zvols:
+        try:
+            await client.call("pool.dataset.delete", [zvol["id"], {"recursive": True}])
+            log.info("  Deleted zvol %r", zvol["id"])
+            deleted += 1
+        except RuntimeError as exc:
+            log.error("  Failed to delete zvol %r: %s", zvol["id"], exc)
+            failed += 1
+    return deleted, failed
+
+
+async def delete_datasets(
+    client: TrueNASClient, datasets: list[dict]
+) -> tuple[int, int]:
+    """
+    Delete datasets deepest-first to avoid parent-before-child errors.
+    Skips pool root datasets (no '/' in the dataset name).
+    Returns (deleted, failed).
+    """
+    sorted_ds = sorted(
+        (d for d in datasets if "/" in d["id"]),
+        key=lambda d: d["id"].count("/"),
+        reverse=True,
+    )
+    deleted = failed = 0
+    for ds in sorted_ds:
+        try:
+            await client.call("pool.dataset.delete", [ds["id"], {"recursive": True}])
+            log.info("  Deleted dataset %r", ds["id"])
+            deleted += 1
+        except RuntimeError as exc:
+            log.error("  Failed to delete dataset %r: %s", ds["id"], exc)
+            failed += 1
+    return deleted, failed