[DEV-747] [DEV-839] [DEV-856] Implement Multi Stream Append

[w1am]

Add support for multi-stream append on the client, matching the server support introduced in version 25.1.

The current limitation is that event data must be valid JSON that can be deserialized into a Dictionary<string, object?>. This is because the new log record properties format is a dictionary. This limitation will be lifted in the next major release of the client, which contains a bunch of developer experience improvements, and allow users to provide their own metadata decoder in the client settings.

This operation takes a list of requests that accept events, along with the expected stream state and stream name. The operation can either fail or succeed, but not both. If it fails, the result will contain a list of failures with additional information, if available.

[linear]

DEV-747 Old .NET Client | Implement Multi append with no schema registry involved

[linear]

DEV-839 .NET client | Document multi stream append

[linear]

DEV-856 .NET Client | Create ISO 8601 Timespan Converter

[Copilot]

Pull Request Overview

This pull request implements multi-stream append functionality in the client library, matching the server support introduced in version 25.1. The implementation adds support for appending events to multiple streams atomically within a single transaction, with optimistic concurrency control for each stream.

Key changes:

• Added MultiStreamAppendAsync method and supporting infrastructure for atomic multi-stream appends
• Introduced new protocol buffer definitions for v2 streams API and error handling
• Refactored test infrastructure with improved configuration management and simplified Docker container setup
• Updated dependency versions and reorganized protobuf file structure

Reviewed Changes

Copilot reviewed 97 out of 99 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/KurrentDB.Client/Streams/KurrentDBClient.MultiAppend.cs	Core implementation of multi-stream append functionality
src/KurrentDB.Client/Streams/Streams/Model/StreamsClientModel.cs	New model types for multi-stream append requests and responses
src/KurrentDB.Client/Streams/Streams/Model/Metadata/MetadataDecoder.cs	Metadata decoding utility for JSON-based event metadata
src/KurrentDB.Client/Core/proto/kurrentdb/protocol/v2/streams/streams.proto	Protocol buffer definitions for v2 streams service
test/KurrentDB.Client.Tests/Streams/MultiStreamAppendTests.cs	Comprehensive tests for multi-stream append functionality
test/KurrentDB.Client.Tests.Common/Fixtures/KurrentDBTemporaryTestNode.cs	Refactored test node setup with improved container management
.github/workflows/test.yml	New unified test workflow replacing multiple legacy workflows
src/KurrentDB.Client/Core/Exceptions/AppendTransactionMaxSizeExceededException.cs	New exception type for transaction size limit violations

Comments suppressed due to low confidence (1)

src/KurrentDB.Client/Streams/Streams/Model/Metadata/MetadataDecoder.cs:1

• The assertion on line 100 will always fail because metadata[\"NullTimeSpanValue\"] is null (as verified by line 90), and calling GetType() on null will throw a NullReferenceException. The test should either not call GetType() on null values or should skip this assertion when the value is null.

// ReSharper disable InconsistentNaming

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[Copilot]

Pull Request Overview

Copilot reviewed 97 out of 99 changed files in this pull request and generated 3 comments.

Comments suppressed due to low confidence (1)

src/KurrentDB.Client/Core/proto/kurrent/rpc/rpc.proto:1

• Corrected spelling of 'propreties' to 'properties'.

// ******************************************************************************************

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[RagingKore]

LGTM