L: E87 slot-map verification wire (S3F19/F20 + F21/F22)

Closes the slot-map verification gap I called out:

  S3F19 / F20  host -> equip: verify expected slot map against what
               the equipment has scanned. Equipment compares element-
               wise; on match drives CSMS NotRead -> Read and replies
               SVACK=Accept; on mismatch drives CSMS -> Mismatched and
               replies SVACK=Mismatch.

  S3F21 / F22  equip -> host: equipment-initiated slot map report
               (typically pushed after CARRIERID is confirmed).

New SVACK enum: SlotMapVerifyAck { Accept, Mismatch, CarrierUnknown,
Error }.  Server dispatch on S3F19 wires the actual CSMS transition
through the CarrierStore from D3.

Two round-trip tests cover both pairs; the FSM-driving behaviour is
exercised through the in-process tests because secs_server.cpp is
the dispatch entry point (no separate integration test needed beyond
the wire round-trip).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

data/messages.yaml

@@ -1335,6 +1335,53 @@ messages:
     builder: s3f26_carrier_transfer_ack
     body: {kind: scalar, item_type: BINARY_BYTE, enum: CarrierActionAck, param: caack}
 
+  # S3F19 / S3F20 — Slot Map Verify.  Host sends its expected slot map
+  # for the carrier; equipment compares against its locally-read map
+  # and replies SVACK (Accept/Mismatch).  On Accept, CSMS transitions
+  # to Read; on Mismatch, CSMS goes to Mismatched.
+  - id: S3F19
+    stream: 3
+    function: 19
+    w: true
+    builder: s3f19_slot_map_verify
+    parser: parse_s3f19
+    body:
+      kind: list
+      struct_name: SlotMapVerifyRequest
+      fields:
+        - {name: carrierid, shape: {kind: scalar, item_type: ASCII}}
+        - name: slots
+          shape: {kind: list_of, element: {kind: scalar, item_type: BINARY_BYTE}}
+
+  - id: S3F20
+    stream: 3
+    function: 20
+    builder: s3f20_slot_map_verify_ack
+    body: {kind: scalar, item_type: BINARY_BYTE, enum: SlotMapVerifyAck, param: svack}
+
+  # S3F21 / S3F22 — Slot Map Report.  Equipment-initiated report of
+  # the slot map it sees (typically pushed after a CARRIERID is read
+  # so the host can decide whether to ProceedWithCarrier).
+  - id: S3F21
+    stream: 3
+    function: 21
+    w: true
+    builder: s3f21_slot_map_report
+    parser: parse_s3f21
+    body:
+      kind: list
+      struct_name: SlotMapReport
+      fields:
+        - {name: carrierid, shape: {kind: scalar, item_type: ASCII}}
+        - name: slots
+          shape: {kind: list_of, element: {kind: scalar, item_type: BINARY_BYTE}}
+
+  - id: S3F22
+    stream: 3
+    function: 22
+    builder: s3f22_slot_map_report_ack
+    body: {kind: scalar, item_type: BINARY_BYTE, enum: SlotMapVerifyAck, param: svack}
+
   # S3F27 / S3F28 — Cancel Carrier (host cancels a carrier operation).
   - id: S3F27
     stream: 3