wire up /score command and debug screen for memory importance

/score snapshots the context and client, releases the agent lock,
runs scoring in background. Only one score task at a time
(scoring_in_flight flag). Results stored on Agent and shown on
the F10 context debug screen with importance scores per memory.

ApiClient derives Clone. ContextState derives Clone.

Co-Authored-By: Proof of Concept <poc@bcachefs.org>

src/subconscious/daemon.rs

@@ -13,7 +13,6 @@
 // Phase 2 will inline job logic; Phase 3 integrates into poc-agent.
 
 use jobkit::{Choir, ExecutionContext, TaskError, TaskInfo, TaskStatus};
-use std::collections::{HashMap, HashSet};
 use std::fs;
 use std::path::{Path, PathBuf};
 use std::sync::{Arc, Mutex};