fix(telegram): fix streaming with extended thinking models overwriting previous messages/ also happens to Execution error (#17973)

Merged via /review-pr -> /prepare-pr -> /merge-pr.

Prepared head SHA: 34b52eead8
Co-authored-by: Marvae <11957602+Marvae@users.noreply.github.com>
Co-authored-by: obviyus <22031114+obviyus@users.noreply.github.com>
Reviewed-by: @obviyus

src/auto-reply/reply/agent-runner-execution.ts

@@ -333,6 +333,7 @@ export async function runAgentTurnWithFallback(params: {
               : undefined,
             onAssistantMessageStart: async () => {
               await params.typingSignals.signalMessageStart();
+              await params.opts?.onAssistantMessageStart?.();
             },
             onReasoningStream:
               params.typingSignals.shouldStartOnReasoning || params.opts?.onReasoningStream
@@ -344,6 +345,7 @@ export async function runAgentTurnWithFallback(params: {
                     });
                   }
                 : undefined,
+            onReasoningEnd: params.opts?.onReasoningEnd,
             onAgentEvent: async (evt) => {
               // Trigger typing when tools start executing.
               // Must await to ensure typing indicator starts before tool summaries are emitted.

src/auto-reply/types.ts

@@ -31,6 +31,10 @@ export type GetReplyOptions = {
   heartbeatModelOverride?: string;
   onPartialReply?: (payload: ReplyPayload) => Promise<void> | void;
   onReasoningStream?: (payload: ReplyPayload) => Promise<void> | void;
+  /** Called when a thinking/reasoning block ends. */
+  onReasoningEnd?: () => Promise<void> | void;
+  /** Called when a new assistant message starts (e.g., after tool call or thinking block). */
+  onAssistantMessageStart?: () => Promise<void> | void;
   onBlockReply?: (payload: ReplyPayload, context?: BlockReplyContext) => Promise<void> | void;
   onToolResult?: (payload: ReplyPayload) => Promise<void> | void;
   /** Called when the actual model is selected (including after fallback).