fix(agents): stop listing soft-deleted agents

Deleting an agent looked like a no-op: it disappeared from the workforce but
stayed on the Team board, and deleting it again did nothing because the row was
already marked. Two queries selected from `agents` without `deleted_at IS NULL`:

  routes/team.rs   the leaderboard — the surface still showing them
  routes/world.rs  the "working" set — a deleted agent holding a stale
                   agent_containers row rendered as live

Observed on this deployment: /api/workforce correctly returned nothing while
/api/team/leaderboard returned two agents soft-deleted back in June.

NOT changed: those rows still exist. Making delete permanent means hard_purge,
which also deletes usage_events — billing history, 6 credits on one of these
two. Discarding that as a side effect of tidying a roster is an explicit
decision, not something a display fix should smuggle in.

.sqlx regenerated: team.rs uses the compile-time-checked query! macro, so the
cached entry no longer matched.

Co-Authored-By: Claude Opus 5 <[email protected]>

crates/cm-api/src/routes/world.rs

@@ -36,7 +36,7 @@ async fn working_agents(pool: &PgPool, ws: WorkspaceId) -> HashSet<String> {
     let rows = sqlx::query(
         "SELECT DISTINCT a.id::text AS id
          FROM agents a JOIN agent_containers ac ON ac.agent_id = a.id
-         WHERE a.workspace_id = $1",
+         WHERE a.workspace_id = $1 AND a.deleted_at IS NULL",
     )
     .bind(ws.as_uuid())
     .fetch_all(pool)