Fix input blocked during scoring: release agent lock before disk write

The scoring callback was holding the agent lock while doing a
synchronous file write (save_memory_scores). This blocked the event
loop from acquiring the lock to process user input.

Fix: collect the scores snapshot while holding the lock, drop the
lock, then write to disk.

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

src/mind/mod.rs

@@ -56,9 +56,9 @@ fn load_memory_scores(section: &mut ContextSection, path: &std::path::Path) {
     }
 }
 
-/// Save all memory scores to disk.
+/// Collect scored memory keys from conversation entries.
-fn save_memory_scores(section: &ContextSection, path: &std::path::Path) {
+fn collect_memory_scores(section: &ContextSection) -> std::collections::BTreeMap<String, f64> {
-    let scores: std::collections::BTreeMap<String, f64> = section.entries().iter()
+    section.entries().iter()
         .filter_map(|ce| {
             if let ConversationEntry::Memory { key, score: Some(s), .. } = &ce.entry {
                 Some((key.clone(), *s))
@@ -66,8 +66,12 @@ fn save_memory_scores(section: &ContextSection, path: &std::path::Path) {
                 None
             }
         })
-        .collect();
+        .collect()
-    if let Ok(json) = serde_json::to_string_pretty(&scores) {
+}
+
+/// 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());
     }
@@ -402,6 +406,7 @@ impl Mind {
                     let agent = agent.clone();
                     let path = scores_path.clone();
                     async move {
+                        let scores_snapshot = {
                             let mut ag = agent.lock().await;
                             for i in 0..ag.context.conversation.len() {
                                 if let ConversationEntry::Memory { key: k, .. } = &ag.context.conversation.entries()[i].entry {
@@ -410,8 +415,12 @@ impl Mind {
                                     }
                                 }
                             }
-                        save_memory_scores(&ag.context.conversation, &path);
                             ag.changed.notify_one();
+                            // Snapshot scores while we have the lock
+                            collect_memory_scores(&ag.context.conversation)
+                        };
+                        // Write to disk after releasing the lock
+                        save_memory_scores(&scores_snapshot, &path);
                     }
                 },
             ).await;