Allow users to ask copilot to use Slack on their behalf via Composio integration.
Adds composio client, OAuth flow, slack skill with tool catalog, and UI for
connecting Slack in onboarding and connectors popover.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Implement a stop execution feature that allows users to abort ongoing LLM
streaming, kill running tool calls, and clear pending permission/human input
requests. Uses a hybrid approach: first click sends graceful SIGTERM, second
click within 2s sends SIGKILL and force-closes MCP clients.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>