Issue #376: Remove StreamingProxy participant double writes

[louis4li]

Issue

Closes #376 — Actorize StreamingProxy orchestration and remove participant double writes

Summary

• Removes the separate StreamingProxy participant actor/store writer path.
• Reads participants from the room actor current-state projection via a query port.
• Keeps the remaining Nyx round-progression actorization as follow-up scope because this PR isolates the participant double-authority defect.

Verification

• dotnet build aevatar.slnx --nologo
• dotnet test test/Aevatar.AI.Tests/Aevatar.AI.Tests.csproj --nologo --no-build
• dotnet test test/Aevatar.Studio.Tests/Aevatar.Studio.Tests.csproj --nologo --no-build
• bash tools/ci/architecture_guards.sh
• bash tools/ci/test_stability_guards.sh
• git diff --check

Follow-up split candidates

1. Actorize StreamingProxy Nyx round progression into room actor continuations.
2. Add a participant read-model freshness contract only if a stable consumer needs version/timestamp visibility.

🤖 Generated by codex-implement-loop. Reviewer is a Claude subagent.

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Activate room projection before dispatching join events

HandleJoinAsync now only dispatches GroupChatParticipantJoinedEvent and returns, but it never ensures the room current-state projection is active first. In this module, the current-state lease is only explicitly activated from StreamingProxyRoomSessionProjectionPort.EnsureProjectionAsync (chat/subscription path), so a join on a room that has not started chat/streaming can be published before any projector subscribes; per IProjectedActor contract this can silently drop materialization, and IStreamingProxyParticipantQueryPort will then return an empty participant list until some later event replays state. This is a user-visible regression for “join then list participants” flows.

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[louis4li]

Review of PR #1024 — round 1

Verdict: rework
Issue: #376 — Actorize StreamingProxy orchestration and remove participant double writes
Head: feat/2026-05-25_issue-376 @ c5d3896
Base: dev
Reviewed by: Claude subagent (codex-implement-loop)

Verdict rationale (one paragraph)

The PR correctly removes the separate StreamingProxy participant write path and moves participant listing onto a room current-state projection, but it leaves the other explicit half of issue #376 unchanged: StreamingProxyNyxParticipantCoordinator still owns the multi-round transcript, active participant set, round loop, failed-participant pruning, and continuation decisions in request-path service-local collections. Because the issue body's suggested direction says to move transcript / round progression / continuation decisions into StreamingProxyGAgent state and event handlers and reduce the coordinator to LLM/Nyx I/O adaptation only, this is not just a follow-up enhancement; it is an unmet acceptance note and must be reworked before pass.

Findings

F1 — Nyx round progression still lives in coordinator-local collections

• Severity: blocking
• Dimension: issue-intent
• Location: agents/Aevatar.GAgents.StreamingProxy/StreamingProxyNyxParticipantCoordinator.cs:96-198
• Evidence:

  var provider = _llmProviderFactory.GetProvider(NyxIdProviderName);
  var transcript = new List<(string Speaker, string Content)>();
  var activeParticipants = participants.ToList();
  var rounds = activeParticipants.Count > 1 ? StreamingProxyDefaults.MaxDiscussionRounds : 1;
  var totalSuccessfulReplies = 0;
  
  for (var round = 1; round <= rounds && activeParticipants.Count > 0; round++)
  {
      var successfulReplies = 0;
      var failedParticipants = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
      var roundParticipants = activeParticipants.ToList();
      ...
      transcript.Add((participant.DisplayName, content));
      ...
      if (failedParticipants.Count > 0)
      {
          activeParticipants = activeParticipants
              .Where(participant => !failedParticipants.Contains(participant.ParticipantId))
              .ToList();
      }
      ...
  }

• Why it's a problem: The issue body explicitly identifies this as part of the defect: "StreamingProxyNyxParticipantCoordinator currently decides rounds, accumulates transcript, and prunes failed participants in middle-layer local state." Its suggested direction says: "Move transcript / round progression / continuation decisions into StreamingProxyGAgent state and event handlers" and "Reduce StreamingProxyNyxParticipantCoordinator to LLM/Nyx I/O adaptation only." The acceptance notes also require "No request-path business progression in coordinator-local collections." The diff only swaps participant writes for projection reads; the request-path coordinator still makes the progression decisions and stores the mutable run facts locally.
• What would change your verdict: Move the transcript, active participant set, round counter, failure pruning, and continue/stop decisions into StreamingProxyGAgent state/event handling. The coordinator should only perform Nyx/LLM I/O for actor-issued work and return/publish the response through an actor continuation event carrying explicit correlation keys such as room/session/round/participant. Add tests that assert the room actor drives round advancement and failure pruning rather than StreamingProxyNyxParticipantCoordinator.GenerateRepliesAsync doing it synchronously in local collections.

What's good

• The separate IStreamingProxyParticipantStore write API and StreamingProxyParticipantGAgent/store actor path are removed from the PR diff, which addresses the participant double-write portion of the issue.
• Participant listing now goes through IStreamingProxyParticipantQueryPort and reads StreamingProxyRoomCurrentStateDocument, aligning reads with a projection of the room actor state.
• The new room current-state projector test verifies the committed room state is materialized with actor id, state version, event id, and typed protobuf StateRoot.

REVIEW_VERDICT:rework:coordinator still owns Nyx round progression

[louis4li]

Review of PR #1024 — round 2

Verdict: pass
Issue: #376 — Actorize StreamingProxy orchestration and remove participant double writes
Head: feat/2026-05-25_issue-376 @ 7922c06
Base: dev
Reviewed by: Claude subagent (codex-implement-loop)

Verdict rationale (one paragraph)

Round 2 resolves the prior blocking gap: the diff now moves Nyx discussion transcript, active participant pruning, round cursor, reply success/failure recording, and terminal continue/stop decisions into StreamingProxyGAgent typed protobuf state and event handlers, while StreamingProxyNyxParticipantCoordinator is reduced to provider discovery plus one Nyx/LLM participant work item that dispatches typed continuation events. The participant double-write portion remains addressed by removing IStreamingProxyParticipantStore, ActorBackedStreamingProxyParticipantStore, and StreamingProxyParticipantGAgent, and by reading participant lists from the room actor current-state projection through IStreamingProxyParticipantQueryPort. Sampled CLAUDE.md anti-patterns did not reveal new blocking violations: the only WriteActor hits in the PR diff are removed lines, and the new state/events are protobuf-defined rather than JSON/custom persisted payloads, matching the CLAUDE.md requirements that "Projection 运行态（会话、订阅、关联）必须由 Actor 或分布式状态承载" and "新增状态/事件/持久化载荷：先定义 .proto 并生成类型".

Findings

No blocking, comment, or nit findings.

What's good (mandatory on pass)

• Round-1 F1 is resolved: StreamingProxyNyxParticipantCoordinator.GenerateRepliesAsync no longer owns transcript, activeParticipants, round loops, failed-participant pruning, or terminal status decisions; the replacement diff adds StreamingProxyGAgent.HandleNyxDiscussionRequested, HandleNyxParticipantReplySucceeded, HandleNyxParticipantReplyFailed, and ContinueNyxDiscussionAsync to drive that progression from actor state.
• The participant double-write path is removed: IStreamingProxyParticipantStore, ActorBackedStreamingProxyParticipantStore, the StreamingProxyParticipantGAgent project, and join/delete/remove store writes are deleted, while participant listing now calls IStreamingProxyParticipantQueryPort.ListAsync against StreamingProxyRoomCurrentStateDocument.
• Tests cover the changed semantics: new/updated tests assert actor-driven failed participant pruning, round advancement, coordinator non-progression behavior, single participant continuation events, endpoint query-port reads, and room current-state projection materialization.

Round comparison

• Findings carried over from round 1: F1 (resolved)
• New findings this round: none
• Net direction: improving

REVIEW_VERDICT:pass:round progression actorized and participant double writes removed