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/knowledge.rs

@@ -102,7 +102,7 @@ pub fn run_and_apply_excluded(
     log: &(dyn Fn(&str) + Sync),
     exclude: &std::collections::HashSet<String>,
 ) -> Result<(), String> {
-    let result = run_one_agent_excluded(store, agent_name, batch_size, llm_tag, log, exclude)?;
+    let _result = run_one_agent_excluded(store, agent_name, batch_size, llm_tag, log, exclude)?;
 
     Ok(())
 }