interop: secsgem-py cross-validation harness + lenient identifier parsing

Adds a Docker-based interop harness that drives the C++ server with
secsgem-py 0.3.0 as the active host and probes a secsgem-py-passive
equipment from a minimal C++ active client.  Surfaces and fixes four
interoperability bugs uncovered by cross-testing:

  * SEMI E5 identifier formatcodes are a U1|U2|U4|U8 wildcard;
    secsgem-py picks the narrowest fitting width while our parsers
    only accepted U4.  `as_uN_scalar` / `as_iN_scalar` now accept
    any unsigned/signed width and range-check the downcast.
  * PPBODY (S7F3/F6) is "ASCII | Binary | List" per the spec;
    secsgem-py defaults to ASCII.  Added BINARY_OR_ASCII codegen
    item type with `as_text_or_binary` accessor.
  * S1F23/F24 Collection Event Namelist was unimplemented; added
    schema + `vids_for(ceid)` accessor on EventReportSubscriptions
    plus the dispatch handler.
  * S10F1 was registered as a host->equipment handler, but per
    SEMI E5 §12 S10F1 is equipment->host; S10F3 is the actual
    host->equipment Terminal Display Single.  Added an S10F3
    handler alongside (we keep S10F1 too for backward compat).

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

data/messages.yaml

@@ -191,6 +191,38 @@ messages:
           - {name: name,  shape: {kind: scalar, item_type: ASCII}}
           - {name: units, shape: {kind: scalar, item_type: ASCII}}
 
+  # S1F23 / S1F24 — Collection Event Namelist (CEID directory).
+  # Body of S1F23 is a list of CEIDs; an empty list means "every CEID".
+  # The S1F24 reply has rows of (CEID, CENAME, [VID...]) listing every
+  # status variable referenced by the reports linked to that CEID.
+  - id: S1F23
+    stream: 1
+    function: 23
+    w: true
+    builder: s1f23_collection_event_namelist_request
+    parser: parse_s1f23
+    body:
+      kind: list_of
+      element: {kind: scalar, item_type: U4}
+      name: ceids
+
+  - id: S1F24
+    stream: 1
+    function: 24
+    builder: s1f24_collection_event_namelist_data
+    parser: parse_s1f24
+    body:
+      kind: list_of
+      name: items
+      element:
+        kind: list
+        struct_name: CollectionEventName
+        fields:
+          - {name: ceid,   shape: {kind: scalar, item_type: U4}}
+          - {name: cename, shape: {kind: scalar, item_type: ASCII}}
+          - name: vids
+            shape: {kind: list_of, element: {kind: scalar, item_type: U4}}
+
   # =====================================================================
   # S2 — Equipment control + reports
   # =====================================================================
@@ -920,7 +952,7 @@ messages:
       struct_name: ProcessProgram
       fields:
         - {name: ppid,   shape: {kind: scalar, item_type: ASCII}}
-        - {name: ppbody, shape: {kind: scalar, item_type: BINARY}}
+        - {name: ppbody, shape: {kind: scalar, item_type: BINARY_OR_ASCII}}
 
   - id: S7F4
     stream: 7
@@ -946,7 +978,7 @@ messages:
       struct_name: ProcessProgram
       fields:
         - {name: ppid,   shape: {kind: scalar, item_type: ASCII}}
-        - {name: ppbody, shape: {kind: scalar, item_type: BINARY}}
+        - {name: ppbody, shape: {kind: scalar, item_type: BINARY_OR_ASCII}}
 
   - id: S7F19
     stream: 7