manager: add optional agent param to GetLooseEnds

GetLooseEnds now takes agent: Option<String>:
- None   = manager's own loose ends (default; the bug fix)
- Some("*")    = hive-wide view (every approval/question/reminder)
- Some("name") = that agent's loose ends

The get_loose_ends MCP tool exposes this as an optional agent arg, so
the manager can still scan the whole swarm on demand. The web UI and
post-turn counts pass None (manager's own).

hive-sh4re/src/lib.rs

@@ -792,12 +792,18 @@ pub enum ManagerRequest {
         #[serde(default)]
         file_path: Option<String>,
     },
-    /// Hive-wide loose-ends view: EVERY pending approval + EVERY
-    /// unanswered question in the swarm. Used by the manager to scan
-    /// for stalled coordination — the per-agent equivalent on the
-    /// sub-agent surface is `AgentRequest::GetLooseEnds` which
-    /// only returns rows where the agent itself is asker / target.
-    GetLooseEnds,
+    /// Loose-ends view for the manager surface. The optional `agent`
+    /// field selects scope:
+    ///   - `None` — the manager's own loose ends: approvals it
+    ///     submitted + questions where it is asker/target + its own
+    ///     pending reminders. This is the default.
+    ///   - `Some("*")` — hive-wide: EVERY pending approval, unanswered
+    ///     question, and pending reminder across the swarm.
+    ///   - `Some("<name>")` — that specific agent's loose ends.
+    GetLooseEnds {
+        #[serde(default)]
+        agent: Option<String>,
+    },
     /// Count of the manager's own pending reminders. Mirror of
     /// `AgentRequest::CountPendingReminders` on the manager surface.
     CountPendingReminders,