Migrate hook observation to runtime events and update the process hook notification protocol. Add runtime event publication for message bus failures, channel lifecycle/outbound flow, gateway reloads, MCP server state, and MCP tool calls.
Validation: go test ./pkg/events/... ./pkg/bus ./pkg/agent ./pkg/channels ./pkg/mcp ./pkg/tools/integration ./pkg/gateway; make lint
Introduce pkg/events with filtered channels, subscription policies, backpressure, and stats. Wire AgentLoop to dual-publish legacy agent events into runtime events while preserving old event APIs.
Validation: go test ./pkg/events/... ./pkg/agent; go test -race ./pkg/events/...; make lint
Hoshina