Share chat context across group turns

[pmbstyle]

Summary

• Share recent conversational history across private and group chat turns through a common conversation scope.
• Pass Telegram and WhatsApp group/private source context into the Octo prompt after group addressing has allowed the turn.
• Keep internal heartbeat, worker, planner, scheduler, and control-plane entries out of conversational recent history.

Why

Addressed group-chat messages should be treated as normal conversation context for the responding agent, while ignored group messages should stay outside memory and model context.

Validation

• uv run ruff check src/octopal/runtime/memory/service.py src/octopal/runtime/octo/prompt_builder.py src/octopal/runtime/octo/router.py src/octopal/runtime/octo/message_runtime.py src/octopal/channels/telegram/handlers.py src/octopal/channels/whatsapp/runtime.py tests/test_memory_system.py tests/test_octo_prompt_history_timestamps.py
• uv run pytest