Fix status bar: show per-section budget breakdown

Budget display shows: sys 12% id 5% jnl 8% conv 40% = 15K/24K
Old conversation log entries silently skipped (journal has context).

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

src/mind/log.rs

@@ -56,6 +56,7 @@ impl ConversationLog {
             if let Ok(node) = serde_json::from_str::<AstNode>(line) {
                 nodes.push(node);
             }
+            // Old format entries silently skipped — journal has the context
         }
         Ok(nodes)
     }