fix(fifa17): carry the manager's item in the squad, not just its id

The operator picked a manager in the FUT hub, then found no manager on the
pre-match squad. The save was NOT the problem: the host logged three
`route=squad-replace status=200 outcome=ok detail=[]` with no unresolved ref,
Core wrote the `squad_managers` row, and every read projected the assignment
back. The client simply had nothing to draw.

`squad.manager[]` was emitted as a bare `[{id, dream}]`. That looked
retail-faithful, and the previous commit defended it on the grounds that no
capture had ever shown otherwise. Re-reading the captures with a populated
manager in hand shows why that was the wrong conclusion: every retail capture
carrying the bare form has `id: 0` — an EMPTY manager. None of them ever
demonstrated that a POPULATED ref renders without its item, because none of them
had one. `plan-2026-08-05-families.md` says as much outright: "FUN_18013d1f0 was
never read for a staff member".

The squad object is self-contained everywhere else: `players[].itemData` carries
the whole card rather than an id resolved out of band. The manager is the same
kind of slot in the same object, and the one implementation that ever drove a
working manager — the Python oracle's squad — emits `id` BESIDE `itemData`.
The element shapes differ and both are now pinned by tests: a player slot is
`{index, itemData, kitNumber}`, the manager is `{id, itemData, dream}`.

So the manager is projected through `resolve_staff` and its item embedded with
`shape_staff_item`, the same 11-key record `/club` serves. An assignment with no
resolvable staff identity still yields `[]` rather than a fabricated ref.

`STAFF_CONTRACT` moves next to `shape_staff_item` in `fut::item` (re-exported
from `club_response`) so `/club` and the squad cannot disagree about the
contract the client checks before kickoff.

Verified on the restored club: userMassInfo, /squad/0 and /squad/active all
carry the manager with resourceId 1000509, contract 7 and the nation/league/team
the client cannot supply itself. Adapter 217 lib + 25 integration, host 114 lib +
36 host_test and every economy suite green.

openfut-adapter-fifa17/src/fut/item.rs

@@ -223,6 +223,14 @@ pub fn shape_kit_item(id: Fifa17KitIdentity, item_state: &str) -> Value {
     })
 }
 
+/// Contracts remaining on an owned staff card.
+///
+/// Staff consume contracts exactly as players do (`rec+0x8c`), and the client
+/// refuses to start a match when the manager's has run out. Core does not model
+/// staff contracts, so this mirrors the constant [`shape_item`] already emits
+/// for players rather than inventing a second, different default.
+pub const STAFF_CONTRACT: i64 = 7;
+
 /// Build one FIFA 17 staff item (manager or coach).
 ///
 /// The key set is deliberately minimal and is taken field-by-field from the