fix(telegram): stop typing indicator when LLM fails or hangs

[kiannidev]

Summary

Fixes #1323 — typing indicator kept running when the LLM failed, timed out, or hung.

Root cause

The cancel function was only invoked in preSend when an outbound message was sent. If the LLM failed or hung, no response was published, so cancel was never called and the typing goroutine ran indefinitely.

Changes

1. Agent loop: Added defer InvokeTypingStop(msg.Channel, msg.ChatID) so typing stops when processing completes (success, error, or panic), regardless of publish.
2. Channels manager: Added InvokeTypingStop(channel, chatID) to invoke the registered typing stop function.
3. Telegram: Added 5-minute context.WithTimeout as fallback so the goroutine exits even if cancel is never called (e.g. LLM hangs).

Testing

• go test ./pkg/channels/... ./pkg/agent/...
• Added unit tests for InvokeTypingStop

[CLAassistant]

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