feat(client-python): add write_array_elements default-fill helper and document semantics

Regenerate Python proto bindings to pick up MxSparseArray/MxSparseElement/
sparse_array_value from the shared mxaccess_gateway.proto. Add
Session.write_array_elements which builds an MxValue(sparse_array_value=…)
from a {index→scalar} dict and delegates to the existing write(). Add 8 pytest
tests covering builder correctness and full round-trip wire shape. Update
README with a default-fill semantics paragraph and bare-name array-write note.

clients/python/src/zb_mom_ww_mxgateway/generated/galaxy_repository_pb2.py

@@ -2,7 +2,7 @@
 # Generated by the protocol buffer compiler.  DO NOT EDIT!
 # NO CHECKED-IN PROTOBUF GENCODE
 # source: galaxy_repository.proto
-# Protobuf Python Version: 6.31.1
+# Protobuf Python Version: 6.33.5
 """Generated protocol buffer code."""
 from google.protobuf import descriptor as _descriptor
 from google.protobuf import descriptor_pool as _descriptor_pool
@@ -12,8 +12,8 @@ from google.protobuf.internal import builder as _builder
 _runtime_version.ValidateProtobufRuntimeVersion(
     _runtime_version.Domain.PUBLIC,
     6,
-    31,
-    1,
+    33,
+    5,
     '',
     'galaxy_repository.proto'
 )

clients/python/src/zb_mom_ww_mxgateway/generated/galaxy_repository_pb2_grpc.py

@@ -5,7 +5,7 @@ import warnings
 
 import galaxy_repository_pb2 as galaxy__repository__pb2
 
-GRPC_GENERATED_VERSION = '1.80.0'
+GRPC_GENERATED_VERSION = '1.81.1'
 GRPC_VERSION = grpc.__version__
 _version_not_supported = False
 
@@ -25,7 +25,7 @@ if _version_not_supported:
     )
 
 
-class GalaxyRepositoryStub(object):
+class GalaxyRepositoryStub:
     """Wire-compatibility policy (ProtobufStyleGuide): this contract evolves
     additively only. Never renumber or repurpose an existing field number or
     enum value. When a field or enum value is removed, add a `reserved` range
@@ -72,7 +72,7 @@ class GalaxyRepositoryStub(object):
                 _registered_method=True)
 
 
-class GalaxyRepositoryServicer(object):
+class GalaxyRepositoryServicer:
     """Wire-compatibility policy (ProtobufStyleGuide): this contract evolves
     additively only. Never renumber or repurpose an existing field number or
     enum value. When a field or enum value is removed, add a `reserved` range
@@ -162,7 +162,7 @@ def add_GalaxyRepositoryServicer_to_server(servicer, server):
 
 
  # This class is part of an EXPERIMENTAL API.
-class GalaxyRepository(object):
+class GalaxyRepository:
     """Wire-compatibility policy (ProtobufStyleGuide): this contract evolves
     additively only. Never renumber or repurpose an existing field number or
     enum value. When a field or enum value is removed, add a `reserved` range

clients/python/src/zb_mom_ww_mxgateway/generated/mxaccess_gateway_pb2_grpc.py

@@ -5,7 +5,7 @@ import warnings
 
 import mxaccess_gateway_pb2 as mxaccess__gateway__pb2
 
-GRPC_GENERATED_VERSION = '1.80.0'
+GRPC_GENERATED_VERSION = '1.81.1'
 GRPC_VERSION = grpc.__version__
 _version_not_supported = False
 
@@ -25,7 +25,7 @@ if _version_not_supported:
     )
 
 
-class MxAccessGatewayStub(object):
+class MxAccessGatewayStub:
     """Wire-compatibility policy (ProtobufStyleGuide): this contract evolves
     additively only. Never renumber or repurpose an existing field number or
     enum value. When a field or enum value is removed, add a `reserved` range
@@ -78,7 +78,7 @@ class MxAccessGatewayStub(object):
                 _registered_method=True)
 
 
-class MxAccessGatewayServicer(object):
+class MxAccessGatewayServicer:
     """Wire-compatibility policy (ProtobufStyleGuide): this contract evolves
     additively only. Never renumber or repurpose an existing field number or
     enum value. When a field or enum value is removed, add a `reserved` range
@@ -189,7 +189,7 @@ def add_MxAccessGatewayServicer_to_server(servicer, server):
 
 
  # This class is part of an EXPERIMENTAL API.
-class MxAccessGateway(object):
+class MxAccessGateway:
     """Wire-compatibility policy (ProtobufStyleGuide): this contract evolves
     additively only. Never renumber or repurpose an existing field number or
     enum value. When a field or enum value is removed, add a `reserved` range

clients/python/src/zb_mom_ww_mxgateway/generated/mxaccess_worker_pb2.py

@@ -2,7 +2,7 @@
 # Generated by the protocol buffer compiler.  DO NOT EDIT!
 # NO CHECKED-IN PROTOBUF GENCODE
 # source: mxaccess_worker.proto
-# Protobuf Python Version: 6.31.1
+# Protobuf Python Version: 6.33.5
 """Generated protocol buffer code."""
 from google.protobuf import descriptor as _descriptor
 from google.protobuf import descriptor_pool as _descriptor_pool
@@ -12,8 +12,8 @@ from google.protobuf.internal import builder as _builder
 _runtime_version.ValidateProtobufRuntimeVersion(
     _runtime_version.Domain.PUBLIC,
     6,
-    31,
-    1,
+    33,
+    5,
     '',
     'mxaccess_worker.proto'
 )

clients/python/src/zb_mom_ww_mxgateway/generated/mxaccess_worker_pb2_grpc.py

@@ -4,7 +4,7 @@ import grpc
 import warnings
 
 
-GRPC_GENERATED_VERSION = '1.80.0'
+GRPC_GENERATED_VERSION = '1.81.1'
 GRPC_VERSION = grpc.__version__
 _version_not_supported = False