Add iSCSI migration support (SCALE archive source)

archive.py:
- Add iscsi_config.json to _CANDIDATES and _KEYWORDS
- parse_archive() now extracts portals, initiators, targets, extents,
  targetextents, and global_config into archive["iscsi"]

migrate.py:
- Add payload builders for all five iSCSI object types
  (extents, initiators, portals, targets, target-extents)
- Add migrate_iscsi() which creates objects in dependency order
  (extents+initiators first, then portals, then targets, then
  target-extent associations) and tracks old→new ID mappings at
  each step so downstream references are correctly remapped
- Conflict detection: extents/targets by name, portals by IP set,
  initiators by comment, target-extents by target+LUN combination
- Skipped objects still populate the ID map so dependent objects
  can remap their references correctly

summary.py:
- Add per-sub-type found/created/skipped/failed counters for iSCSI
- iSCSI rows appear in the report only when iSCSI data was processed

cli.py:
- Add _prompt_iscsi_portals() — shows source IPs per portal and
  prompts for destination IPs in-place; supports MPIO (space-separated)
- Wizard scope menu gains option 3 (iSCSI); portal prompt fires
  automatically after archive parse when iSCSI portals are present
- run() wires in migrate_iscsi()
- argparse --migrate now accepts "iscsi" as a valid choice

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

truenas_migrate/summary.py

@@ -21,12 +21,43 @@ class Summary:
     nfs_skipped: int = 0
     nfs_failed:  int = 0
 
+    iscsi_extents_found:       int = 0
+    iscsi_extents_created:     int = 0
+    iscsi_extents_skipped:     int = 0
+    iscsi_extents_failed:      int = 0
+
+    iscsi_initiators_found:    int = 0
+    iscsi_initiators_created:  int = 0
+    iscsi_initiators_skipped:  int = 0
+    iscsi_initiators_failed:   int = 0
+
+    iscsi_portals_found:       int = 0
+    iscsi_portals_created:     int = 0
+    iscsi_portals_skipped:     int = 0
+    iscsi_portals_failed:      int = 0
+
+    iscsi_targets_found:       int = 0
+    iscsi_targets_created:     int = 0
+    iscsi_targets_skipped:     int = 0
+    iscsi_targets_failed:      int = 0
+
+    iscsi_targetextents_found:   int = 0
+    iscsi_targetextents_created: int = 0
+    iscsi_targetextents_skipped: int = 0
+    iscsi_targetextents_failed:  int = 0
+
     errors: list[str] = field(default_factory=list)
 
     # Populated during dry-run dataset safety checks
     paths_to_create:  list[str] = field(default_factory=list)
     missing_datasets: list[str] = field(default_factory=list)
 
+    @property
+    def _has_iscsi(self) -> bool:
+        return (self.iscsi_extents_found + self.iscsi_initiators_found +
+                self.iscsi_portals_found + self.iscsi_targets_found +
+                self.iscsi_targetextents_found) > 0
+
     def report(self) -> str:
         w = 60
 
@@ -34,6 +65,14 @@ class Summary:
             s = f"{label}={n}"
             return color_fn(s) if n > 0 else _dim(s)
 
+        def _iscsi_val(found, created, skipped, failed) -> str:
+            return (
+                f"{_dim('found=' + str(found))}  "
+                f"{_stat('created', created, _bold_green)}  "
+                f"{_stat('skipped', skipped, _yellow)}  "
+                f"{_stat('failed',  failed,  _bold_red)}"
+            )
+
         smb_val = (
             f"{_dim('found=' + str(self.smb_found))}  "
             f"{_stat('created', self.smb_created, _bold_green)}  "
@@ -67,11 +106,30 @@ class Summary:
             f"{tl}{hr}{tr}",
             title_row,
             f"{ml}{hr}{mr}",
-            row("SMB shares :  ", smb_val),
-            row("NFS shares :  ", nfs_val),
-            f"{bl}{hr}{br}",
+            row("SMB shares    :  ", smb_val),
+            row("NFS shares    :  ", nfs_val),
         ]
 
+        if self._has_iscsi:
+            lines.append(f"{ml}{hr}{mr}")
+            lines.append(row("iSCSI extents :  ", _iscsi_val(
+                self.iscsi_extents_found, self.iscsi_extents_created,
+                self.iscsi_extents_skipped, self.iscsi_extents_failed)))
+            lines.append(row("iSCSI initiators: ", _iscsi_val(
+                self.iscsi_initiators_found, self.iscsi_initiators_created,
+                self.iscsi_initiators_skipped, self.iscsi_initiators_failed)))
+            lines.append(row("iSCSI portals :  ", _iscsi_val(
+                self.iscsi_portals_found, self.iscsi_portals_created,
+                self.iscsi_portals_skipped, self.iscsi_portals_failed)))
+            lines.append(row("iSCSI targets :  ", _iscsi_val(
+                self.iscsi_targets_found, self.iscsi_targets_created,
+                self.iscsi_targets_skipped, self.iscsi_targets_failed)))
+            lines.append(row("iSCSI tgt↔ext :  ", _iscsi_val(
+                self.iscsi_targetextents_found, self.iscsi_targetextents_created,
+                self.iscsi_targetextents_skipped, self.iscsi_targetextents_failed)))
+
+        lines.append(f"{bl}{hr}{br}")
+
         if self.errors:
             lines.append(f"\n  {_bold_red(str(len(self.errors)) + ' error(s):')} ")
             for e in self.errors: