test: verbose mode tool events as new messages + integration tests

Adds TestVerboseMode_ToolEventsSendNewMessages and
TestEngagingMode_UpdatesProgressMessage — full integration tests
with mock LLM + mock Telegram API servers that verify:

Verbose mode:
- Thinking notes (💭) sent via SendMessage (new messages)
- Tool calls (🔧) sent via SendMessage (new messages)
- Tool results (✅) sent via SendMessage (new messages)
- Stale tool_call messages deleted
- EditMessageText NEVER called

Engaging mode:
- Progress message updated via EditMessageText (expected)

Author: molty3000