feat(#2569): DB-backed per-agent todo store + mcp.sock upsert/clear/list/mark-done ops

hive-agent-mcp/src/mcp/render.rs

@@ -228,6 +228,27 @@ pub(super) fn render_loose_ends(loose_ends: &[hive_sh4re::LooseEnd]) -> String {
                     );
                 }
             }
+            hive_sh4re::LooseEnd::Todo {
+                id,
+                subsystem,
+                subsystem_key,
+                summary,
+                source,
+                age_seconds,
+            } => {
+                let key = subsystem_key
+                    .as_deref()
+                    .map(|k| format!(" {k}"))
+                    .unwrap_or_default();
+                let src = source
+                    .as_deref()
+                    .map(|s| format!(" — {s}"))
+                    .unwrap_or_default();
+                let _ = writeln!(
+                    out,
+                    "- todo #{id} [{subsystem}{key}, {age_seconds}s old]: {summary}{src} (mark_todo_done to clear)"
+                );
+            }
         }
     }
     out