D2: E87 wire messages (S3F17/F18 + F23/F24 + F25/F26 + F27/F28)

Adds the Carrier Management wire surface that drives the FSMs from D1:

  S3F17 / S3F18  CarrierAction (host issues ProceedWithCarrier /
                 CancelCarrier / BindCarrierID / etc.; CommandParameter
                 list is reused from S2F41).
  S3F23 / S3F24  PortGroupChangeReport (equipment notifies host of port
                 group composition changes).
  S3F25 / S3F26  CarrierTransfer (host instructs source -> target port
                 transfer).
  S3F27 / S3F28  CancelCarrier (host cancels an outstanding carrier op).

Two new ack enums in messages_helpers.hpp:
  CarrierActionAck — CAACK byte; covers the common error responses
                     (CarrierIDUnknown, Inaccessible, ActionInProgress).
  PortGroupAck     — PGACK byte (Accept / Error).

Round-trip tests for all four pairs.  Server-side dispatch + the
CarrierStore + LoadPortStore that the FSMs key into land in D3/D4.

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

data/messages.yaml

@@ -1246,6 +1246,110 @@ messages:
         - {name: mapercd, shape: {kind: scalar, item_type: BINARY_BYTE}}
         - {name: errtext, shape: {kind: scalar, item_type: ASCII}}
 
+  # =====================================================================
+  # S3 — E87 Carrier Management.
+  #
+  # CARRIERID is an ASCII identifier (per E87-0716 §10.2 typically up to
+  # 40 chars).  CAACK is the host/equipment ack byte for carrier-action
+  # requests, modelled here as CarrierActionAck.  PORTID is U1, SLOTID
+  # is U1.  We carry only the most common subset of S3 here; richer
+  # forms (E14 generic ObjectService) are YAML extension points.
+  # =====================================================================
+
+  # S3F17 / S3F18 — CarrierAction.  Host instructs equipment to perform
+  # a carrier-level operation (ProceedWithCarrier, CancelCarrier,
+  # CancelCarrierAtPort, BindCarrierID, ResetCarrier, ...). The list of
+  # parameters is action-specific; we carry it as a parallel name/value
+  # list mirroring S2F41's CommandParameter shape.
+  - id: S3F17
+    stream: 3
+    function: 17
+    w: true
+    builder: s3f17_carrier_action
+    parser: parse_s3f17
+    body:
+      kind: list
+      struct_name: CarrierActionRequest
+      fields:
+        - {name: dataid,    shape: {kind: scalar, item_type: U4}}
+        - {name: carrieraction, shape: {kind: scalar, item_type: ASCII}}
+        - {name: carrierid,     shape: {kind: scalar, item_type: ASCII}}
+        - name: params
+          shape:
+            kind: list_of
+            element:
+              kind: list
+              struct_name: CommandParameter
+              external_struct: true
+              fields:
+                - {name: name,  shape: {kind: scalar, item_type: ASCII}}
+                - {name: value, shape: {kind: scalar, item_type: ITEM}}
+
+  - id: S3F18
+    stream: 3
+    function: 18
+    builder: s3f18_carrier_action_ack
+    body: {kind: scalar, item_type: BINARY_BYTE, enum: CarrierActionAck, param: caack}
+
+  # S3F23 / S3F24 — Port Group Change Report (equipment notifies host of
+  # a port-grouping change; E87-0716 §10.4).
+  - id: S3F23
+    stream: 3
+    function: 23
+    w: true
+    builder: s3f23_port_group_change_report
+    parser: parse_s3f23
+    body:
+      kind: list
+      struct_name: PortGroupChangeReport
+      fields:
+        - {name: ctngrpid, shape: {kind: scalar, item_type: ASCII}}
+        - name: portids
+          shape: {kind: list_of, element: {kind: scalar, item_type: U1}}
+
+  - id: S3F24
+    stream: 3
+    function: 24
+    builder: s3f24_port_group_change_ack
+    body: {kind: scalar, item_type: BINARY_BYTE, enum: PortGroupAck, param: pgack}
+
+  # S3F25 / S3F26 — Carrier Transfer (host instructs equipment to move
+  # a carrier between source and target ports).
+  - id: S3F25
+    stream: 3
+    function: 25
+    w: true
+    builder: s3f25_carrier_transfer
+    parser: parse_s3f25
+    body:
+      kind: list
+      struct_name: CarrierTransferRequest
+      fields:
+        - {name: carrierid,    shape: {kind: scalar, item_type: ASCII}}
+        - {name: source_portid, shape: {kind: scalar, item_type: U1}}
+        - {name: target_portid, shape: {kind: scalar, item_type: U1}}
+
+  - id: S3F26
+    stream: 3
+    function: 26
+    builder: s3f26_carrier_transfer_ack
+    body: {kind: scalar, item_type: BINARY_BYTE, enum: CarrierActionAck, param: caack}
+
+  # S3F27 / S3F28 — Cancel Carrier (host cancels a carrier operation).
+  - id: S3F27
+    stream: 3
+    function: 27
+    w: true
+    builder: s3f27_cancel_carrier
+    parser: parse_s3f27
+    body: {kind: scalar, item_type: ASCII, param: carrierid}
+
+  - id: S3F28
+    stream: 3
+    function: 28
+    builder: s3f28_cancel_carrier_ack
+    body: {kind: scalar, item_type: BINARY_BYTE, enum: CarrierActionAck, param: caack}
+
   # =====================================================================
   # S14 — Object services (E94 ControlJob create/delete).
   #