mind: trigger incremental scoring on startup + log persist path

Two changes to make scoring debuggable and self-starting:

1. init() kicks off start_memory_scoring() after restore_from_log +
   load_memory_scores. No user message needed to exercise the
   incremental path.

2. Diagnostic logging around the on_score persist path:
   - [scoring] persisted K → N.NNN (Section[i]) read_back=Some(...)
     when find_memory_by_key succeeds and set_score stores the score
     (with a read-back check on the leaf).
   - [scoring] DROP K: find_memory_by_key None (id=N, cv=M)
     when the scored key isn't findable in the live context — with
     section sizes to diagnose whether content shrank.
   - [scoring] snapshot size=N contains(K)=true/false
     after collect_memory_scores, to catch the case where set_score
     claims to have written but collect doesn't see it.
   - [scoring] about to save N entries
   - save_memory_scores now also logs serialize/write errors so a
     silent write failure isn't invisible.

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

src/mind/mod.rs

@@ -103,9 +103,13 @@ fn collect_memory_scores(ctx: &ContextState) -> std::collections::BTreeMap<Strin
 
 /// Save memory scores to disk.
 fn save_memory_scores(scores: &std::collections::BTreeMap<String, f64>, path: &std::path::Path) {
-    if let Ok(json) = serde_json::to_string_pretty(scores) {
-        let _ = std::fs::write(path, json);
-        dbglog!("[scoring] saved {} scores to {}", scores.len(), path.display());
+    match serde_json::to_string_pretty(scores) {
+        Ok(json) => match std::fs::write(path, &json) {
+            Ok(()) => dbglog!("[scoring] saved {} scores to {} ({} bytes)",
+                scores.len(), path.display(), json.len()),
+            Err(e) => dbglog!("[scoring] save FAILED ({}): {}", path.display(), e),
+        },
+        Err(e) => dbglog!("[scoring] serialize FAILED: {}", e),
     }
 }
 
@@ -506,6 +510,17 @@ impl Mind {
         // Load persistent subconscious state
         let state_path = self.config.session_dir.join("subconscious-state.json");
         self.subconscious.lock().await.set_state_path(state_path);
+
+        // Kick off an incremental scoring pass on startup so memories due
+        // for re-scoring get evaluated without requiring a user message.
+        {
+            let mut s = self.shared.lock().unwrap();
+            if !s.scoring_in_flight {
+                s.scoring_in_flight = true;
+                drop(s);
+                self.start_memory_scoring();
+            }
+        }
     }
 
     pub fn turn_watch(&self) -> tokio::sync::watch::Receiver<bool> {
@@ -619,14 +634,40 @@ impl Mind {
                             let mut ctx = agent.context.lock().await;
                             // Find memory by key in identity or conversation
                             let found = find_memory_by_key(&ctx, &key);
-                            if let Some((section, i)) = found {
+                            match found {
+                                Some((section, i)) => {
                                     ctx.set_score(section, i, Some(score));
+                                    let nodes: &[crate::agent::context::AstNode] = match section {
+                                        Section::Identity => ctx.identity(),
+                                        Section::Conversation => ctx.conversation(),
+                                        _ => &[],
+                                    };
+                                    let read_back = match nodes.get(i) {
+                                        Some(crate::agent::context::AstNode::Leaf(l)) => match l.body() {
+                                            crate::agent::context::NodeBody::Memory { score, .. } => format!("{:?}", score),
+                                            _ => "not-memory".to_string(),
+                                        },
+                                        _ => "out-of-bounds".to_string(),
+                                    };
+                                    dbglog!("[scoring] persisted {} → {:.3} ({:?}[{}]) read_back={}",
+                                        key, score, section, i, read_back);
+                                }
+                                None => {
+                                    dbglog!(
+                                        "[scoring] DROP {}: find_memory_by_key None (id={}, cv={})",
+                                        key, ctx.identity().len(), ctx.conversation().len()
+                                    );
+                                }
                             }
                             let snapshot = collect_memory_scores(&ctx);
+                            let in_snapshot = snapshot.contains_key(&key);
+                            dbglog!("[scoring] snapshot size={} contains({})={}",
+                                snapshot.len(), key, in_snapshot);
                             drop(ctx);
                             agent.state.lock().await.changed.notify_one();
                             snapshot
                         };
+                        dbglog!("[scoring] about to save {} entries", scores_snapshot.len());
                         save_memory_scores(&scores_snapshot, &path);
                     }
                 },