manager mcp: expose 'remind' tool sharing storage helper with agent surface

hive-sh4re/src/lib.rs

@@ -486,6 +486,17 @@ pub enum ManagerRequest {
         #[serde(default)]
         lines: Option<u32>,
     },
+    /// Mirror of `AgentRequest::Remind` on the manager surface — schedule
+    /// a reminder addressed to the manager itself. Same semantics: body
+    /// soft-caps at 1 KiB, oversize bodies auto-persist to
+    /// `/state/reminders/auto-<ts>.md` (the manager container's own state
+    /// mount) and the inbox sees a pointer.
+    Remind {
+        message: String,
+        timing: ReminderTiming,
+        #[serde(default)]
+        file_path: Option<String>,
+    },
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize)]