fix-codex round-3: address PR #687 v4 reviewer demands (cluster-024) — last round

Applied 4 fixes (FIX_DONE:687:round-3:applied-4:rejected-0:blocked-0):
- (A) architect: add missing Refactor (iter15/cluster-024) anchor on
  AIGAgentBase.cs:202 documenting the deleted protected ChatAsync helper
  surface (subclasses now use ChatStreamAsync + local aggregation only
  when needed)
- (A) architect: remove inaccurate Refactor comment from
  ScriptGenerateGAgent.GenerateWithReasoningAsync — that method was
  already streaming on origin/dev. Only GenerateAsync keeps the
  direct-ChatAsync refactor comment
- (A) architect: same removal on WorkflowGenerateGAgent.GenerateWithReasoningAsync
- (A) tests: widen ChatRuntimeStreamingBufferTests source-regression
  scan from src/Aevatar.AI.Core only to: src/Aevatar.AI.Core +
  src/Aevatar.Studio.Hosting + agents/Aevatar.GAgents.ChatbotClassifier,
  ignoring provider-boundary abstractions and comment-only lines

Build pass; Aevatar.AI.Tests 558 pass; Aevatar.Studio.Tests 521 pass;
test_stability_guards pass; git diff --check pass.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: loning

src/Aevatar.AI.Core/AIGAgentBase.cs

@@ -199,6 +199,9 @@ protected sealed override AIAgentConfig MergeEffectiveConfig(AIAgentConfig class
         return merged;
     }
 
+    // Refactor (iter15/cluster-024):
+    //   Old pattern: protected ChatAsync helpers let GAgents call the non-streaming executor as a formal conversation path.
+    //   New principle: GAgent subclasses use ChatStreamAsync; explicit offline aggregation is local to the caller that needs text.
     /// <summary>流式 Chat。</summary>
     protected IAsyncEnumerable<LLMStreamChunk> ChatStreamAsync(string userMessage, CancellationToken ct = default)
     {

src/Aevatar.Studio.Hosting/Endpoints/ScriptGenerateGAgent.cs

@@ -54,9 +54,6 @@ protected override AIAgentConfigStateOverrides ExtractStateConfigOverrides(Empty
         Func<string, CancellationToken, Task>? onReasoning,
         CancellationToken ct = default)
     {
-        // Refactor (iter15/cluster-024):
-        //   Old pattern: non-streaming ChatAsync directly called provider.ChatAsync.
-        //   New principle: ChatStreamAsync is the only authoritative AI executor; offline text aggregation consumes the stream as an explicit adapter.
         var content = new StringBuilder();
         await foreach (var chunk in ChatStreamAsync(prompt, requestId, metadata, ct))
         {

src/Aevatar.Studio.Hosting/Endpoints/WorkflowGenerateGAgent.cs

@@ -54,9 +54,6 @@ protected override AIAgentConfigStateOverrides ExtractStateConfigOverrides(Empty
         Func<string, CancellationToken, Task>? onReasoning,
         CancellationToken ct = default)
     {
-        // Refactor (iter15/cluster-024):
-        //   Old pattern: non-streaming ChatAsync directly called provider.ChatAsync.
-        //   New principle: ChatStreamAsync is the only authoritative AI executor; offline text aggregation consumes the stream as an explicit adapter.
         var content = new StringBuilder();
         await foreach (var chunk in ChatStreamAsync(prompt, requestId, metadata, ct))
         {

test/Aevatar.AI.Tests/ChatRuntimeStreamingBufferTests.cs

@@ -387,11 +387,17 @@ public async Task ChatAsync_WhenProviderStreamsContent_ShouldAggregateWithoutCal
     }
 
     [Fact]
-    public void AiCoreSource_ShouldNotDirectlyCallProviderChatAsyncOutsideProviderBoundary()
+    public void UserFacingAiExecutorSurfaces_ShouldNotDirectlyCallProviderChatAsyncOutsideProviderBoundary()
     {
         var root = FindRepositoryRoot();
-        var aiCore = Path.Combine(root, "src", "Aevatar.AI.Core");
-        var offenders = Directory.EnumerateFiles(aiCore, "*.cs", SearchOption.AllDirectories)
+        var scannedRoots = new[]
+        {
+            Path.Combine(root, "src", "Aevatar.AI.Core"),
+            Path.Combine(root, "src", "Aevatar.Studio.Hosting"),
+            Path.Combine(root, "agents", "Aevatar.GAgents.ChatbotClassifier"),
+        };
+        var offenders = scannedRoots
+            .SelectMany(scanRoot => Directory.EnumerateFiles(scanRoot, "*.cs", SearchOption.AllDirectories))
             .SelectMany(file => File.ReadLines(file)
                 .Select((line, index) => new { file, line, index })
                 .Where(x => !x.line.TrimStart().StartsWith("//", StringComparison.Ordinal))