fix: emit completed tool events after interruption

[chenghao-mou]

Problem: Completed non-handoff tool results survived parent speech interruption, but function_tools_executed was skipped. Event listeners could not speak or process those results.

Emit the event for the same safe outputs already committed by interruption recovery. Keep interrupted handoffs excluded so they remain retryable. Add a regression covering the listener's uninterruptible session.say.

Addresses AGT-3283

Initial prompt and agent context

Model: GPT-5.6

if I have a say call with allow_interruptions=False in a event handler (function tool executed), but can new user speech or transcript still interrupted it?

/Users/chenghao/Downloads/observability-RM_vCuegQdTaXSk you can see there is a 2ms agent speech that is interrupted

we need to fix that. I think the customer was right about this linear: AGT-3283

[devin-ai-integration]

✅ Devin Review: No Issues Found

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