fix(fifa17): a dangling manager ref must not refuse the squad save

Every real squad save was failing with 400 unresolved_wire_ids. Reproduced on
staging with the repo's own seeder, which sends the captured retail body:

  route=squad-replace status=400 outcome=unresolved_wire_ids detail=[[100000427]]

FIFA 17 always sends a manager ref, and on a real profile it does not resolve to
an owned instance. scripts/sold-staging-seed-squad.py already recorded why:
production's own squad points at instance 100000427, which is absent from
production's /club/staff (1975 items spanning 100000001..100004826), and the
client accepts that squad back unchanged -- so the client never validates the
manager against the club, and the pre-0023 server accepted it.

Making the manager ownership-backed (d37a9d5 / 25f4ad1) turned that ref into a
hard refusal, which took out the primary FUT write path: no squad save means no
squad, which means the client will not enter the FUT hub at all.

A manager ref is not a squad slot. An unresolvable PLAYER slot must still refuse
the save -- committing it would silently drop an owned card from the club. An
unresolvable MANAGER ref just means there is no ownership-backed manager, which
is exactly the state before migration 0023: the save commits, the assignment is
cleared as a full replacement should, and the id is reported on
ProposedSquad::unresolved_manager_wire_id so the host can log what it could not
map instead of letting it vanish. A ref that DOES resolve is still assigned and
still authorized against the club.

Verified end to end on staging: the seeder now answers {"id": 0} with 11
occupied slots, the host logs
`manager_ref_unresolved=100000427 (saved with no manager assignment)`, and the
projected squad carries `manager: []`.

openfut-utas-host/src/lib.rs

@@ -2131,6 +2131,17 @@ pub fn handle_put_squad(body: &[u8], deps: &SquadDeps<'_>) -> (WireResponse, Squ
             );
         }
     }
+    // FIFA always sends a manager ref, and on a real profile it does not resolve
+    // to an owned instance (production's own save points at 100000427, absent
+    // from its /club/staff). That is not an error: the save commits with NO
+    // ownership-backed manager. Logged so a ref we cannot map stays visible
+    // instead of vanishing.
+    if let Some(wire) = build.canonical.unresolved_manager_wire_id {
+        eprintln!(
+            "utas-host owner=RUST route=squad-replace manager_ref_unresolved={wire} \
+             (saved with no manager assignment)"
+        );
+    }
     // Commit canonical + extension atomically. No Python fallback on failure.
     let req = CoreReplaceRequest {
         name: build.canonical.name.clone(),