The background daemon and its job orchestration are redundant now that
the consciousness binary handles everything directly. Gut daemon.rs
down to just GraphHealth + compute_graph_health (used by the F4 TUI
screen), remove the DaemonCmd CLI subcommand, strip daemon RPC
fast-paths from cli/agent.rs, and drop the jobkit dependency.
-1330 lines.
Co-Authored-By: Proof of Concept <poc@bcachefs.org>