metrics + overview: stop counting utility accounts as members, and surface agent usage

The panel has always excluded operator/utility emails from member counts
(OPERATOR_EMAILS), but the metrics counted every row in the members table, so the
panel said 75 while every metric surface said 76. The one affected row is
info@inference.coop — the reading mailbox, not a person.

- metrics_snapshot.py now applies the same OPERATOR_EMAILS definition (same variable
  name, same default) so the two cannot drift apart again. No backfill: history stays
  as published and the daily job writes the corrected value going forward.
- admin_overview now also returns an `agents` list, built from the LiteLLM teams it
  already fetches (anything not member:*), so bot and sandbox spend is visible rather
  than structurally invisible. Kept out of member counts and member aggregates, like
  the operator category.

app/main.py

@@ -3131,9 +3131,25 @@ async def admin_overview(request: Request):
             total_spend += spend
             total_all_time += member_all_time
 
+    # Bot and sandbox teams: real spend, but not members. Surfaced in their own
+    # category so the co-op's own usage is accountable without inflating member
+    # counts — the same reasoning as the operator accounts above.
+    agents = [
+        {
+            "alias": alias,
+            "spend": float(t.get("spend") or 0.0),
+            "budget": t.get("max_budget"),
+            "team_members": len(t.get("members_with_roles") or []),
+        }
+        for alias, t in teams.items()
+        if alias and not alias.startswith("member:")
+    ]
+    agents.sort(key=lambda a: a["spend"], reverse=True)
+
     return {
         "members": members,
         "admins": admins,
+        "agents": agents,
         "totals": {
             "members": len(members),
             "active": sum(1 for m in members if m["active"]),