harness metrics for tool calls, bash commands, reminders and first-turn context, on the agents board

The per-agent /stats page read these from its sqlite; the swarm board had
none of them. hive-agent now counts the tools a turn called, the commands
bash tasks ran (from the bash daemon's own table, newer rows only),
reminders scheduled and delivered, and records the first turn of a fresh
session; the turns tab shows them, with fresh sessions per agent. Claude's
own export has no tool-call counter, so the docs no longer say it does.

hive-agent/src/reminders.rs

@@ -88,6 +88,7 @@ impl Reminders {
              VALUES (?1, ?2, ?3, ?4, NULL)",
             params![message, file_path, due_at, now],
         )?;
+        crate::otel_turn_metrics::record_reminder("scheduled");
         Ok(conn.last_insert_rowid())
     }
 
@@ -173,6 +174,7 @@ impl Reminders {
             "UPDATE reminders SET sent_at = ?1 WHERE id = ?2",
             params![Utc::now().timestamp(), id],
         )?;
+        crate::otel_turn_metrics::record_reminder("delivered");
         Ok(())
     }