Memory scores on entries, not a separate Vec

ConversationEntry::Memory gains score: Option<f64>. The scorer
writes scores directly onto entries when results arrive. Removes
Agent.memory_scores Vec and the memory_scores parameter from
context_state_summary().

Scores are serialized to/from the conversation log as memory_score.

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

src/user/chat.rs

@@ -863,7 +863,7 @@ impl ScreenView for InteractScreen {
             agent.expire_activities();
             app.status.prompt_tokens = agent.last_prompt_tokens();
             app.status.model = agent.model().to_string();
-            let sections = agent.context_state_summary(None);
+            let sections = agent.context_state_summary();
             app.status.context_budget = crate::agent::context::sections_budget_string(&sections);
             app.activity = agent.activities.last()
                 .map(|a| a.label.clone())

src/user/context.rs

@@ -29,7 +29,7 @@ impl ConsciousScreen {
 
     fn read_context_state(&self) -> Vec<ContextSection> {
         match self.agent.try_lock() {
-            Ok(ag) => ag.context_state_summary(None),
+            Ok(ag) => ag.context_state_summary(),
             Err(_) => Vec::new(),
         }
     }