feat(core): one instance-based ownership model for every kind of owned content

Core could only own players. Everything else a FUT club holds — managers, staff,
consumables, kits, badges, balls, stadiums — had no representation, so the only
way to show one to a client was to synthesise it on read. That is the failure
mode this commit exists to make impossible: read authority, write authority and
persistent ownership authority are now the same rows.

MODEL. There is deliberately NO parallel items table. A manager, a consumable, a
kit and a player are all rows in `owned_cards`, differing only by a new
game-INDEPENDENT `content_kind` (player|manager|staff|consumable|kit|badge|ball|
stadium|misc). A game adapter translates its own taxonomy — FIFA 17's
`cardsubtypeid` and resource ranges — into one of those tokens before ownership
reaches Core; no game's numerics land here. Ownership stays INSTANCE-based:
`card_id` is the definition, `id` is the instance, and two copies of one
definition remain two rows.

`quantity` is a nullable per-instance attribute, not a replacement for the
instance. The real profile settles this: its 17 consumables are instance-based
and only SOME carry a wire `amount` (observed 1,2,4,5,10,15), while two copies of
definition 5003068 exist as two distinct instances. So NULL means "not a stack"
and a positive integer is the stack size; collapsing instances into counts is
forbidden by the model.

ACTIVE DESIGNATIONS. Migration 0024's two-slot kit table becomes
`club_active_items` over the five slots that correspond exactly to the client's
recovered equipped-state vocabulary (activeBadge 100, activeHomeKit 101,
activeAwayKit 102, activeBall 103, activeStadium 104). There is no
activeLeagueLogo or activeMisc token, so those kinds correctly get no slot. The
invariants are schema-enforced rather than conventional: PK(club_id, slot) allows
at most one item per role, `owned_card_id UNIQUE` makes "the same card is both
home and away kit" unstorable, and ON DELETE CASCADE means a quick-sold or
consumed item cannot be projected back as active. 0024's trigger is preserved in
semantics — and dropped EXPLICITLY before its table, because it lives ON
`owned_cards`, so DROP TABLE would have orphaned it and broken every later
ownership transfer. It still exists because the market moves ownership by UPDATE,
which no foreign key can observe.

CONSUMABLE ACTIONS. `services/consume.rs` is one transaction primitive —
validate source ownership and kind, validate target, mutate, consume the source
exactly once, commit — guarded by `UNIQUE(profile_id, action_identity)` in
migration 0027, the same discipline as `match_completions`. It supports both
deleting the row and decrementing a stack, chosen by the caller, inside the one
transaction and the one replay guard. It deliberately contains NO category
formulas: an unreversed effect must not be invented, so callers supply the
mutation and category validation stays explicit.

`/club/kits` is replaced by slot-generic `/club/active-items`. `get_collection`
now carries `content_kind` and `quantity`, accepts a `content_kind` filter, and
— importantly — stops dropping an owned card with a missing definition silently:
the envelope reports `owned_rows`, `unresolved_items` and the offending
definition ids. That silent `filter_map` is the documented cause of a club that
looks empty while the rows are all present.

Verified against a REAL populated club, not a fixture: the production snapshot
(migration 19) is copied to a tempdir, migrated to 0024, given two kit
designations on real owned instances, then migrated to head. 1986 owned rows
survive as content_kind='player', both designations land in `club_active_items`,
no row gains a quantity, and the old table is gone. 258 tests pass, clippy clean.

migrations/0026_club_active_items.sql

@@ -0,0 +1,55 @@
+-- Generalise the two-slot kit designation (migration 0024) into the full set of
+-- active club designations.
+--
+-- Ownership still lives ONLY in `owned_cards`; this table records which owned
+-- INSTANCE currently occupies each club-scoped role. A row here is a pointer,
+-- never a second ownership authority.
+--
+-- Lifecycle invariants enforced by the schema, not by convention:
+--   * `PRIMARY KEY (club_id, slot)` — at most one active item per role.
+--   * `owned_card_id ... UNIQUE` — one owned instance can occupy at most ONE
+--     slot, so "the same card is both the home and the away kit" is unstorable.
+--   * `REFERENCES owned_cards(id) ON DELETE CASCADE` — quick-selling/consuming
+--     the item removes the designation, so a sold item can never be projected
+--     back to the client as active.
+--   * the BEFORE UPDATE trigger below — a market transfer moves ownership by
+--     UPDATE (the row id survives), which no FK action can see, so the
+--     designation is dropped explicitly before the owner changes.
+--
+-- `squad_managers` (migration 0023) is squad-scoped, not club-scoped, and is
+-- deliberately NOT folded in here.
+CREATE TABLE IF NOT EXISTS club_active_items (
+    club_id       TEXT NOT NULL REFERENCES clubs(id) ON DELETE CASCADE,
+    slot          TEXT NOT NULL CHECK (slot IN (
+                      'home_kit', 'away_kit', 'badge', 'ball', 'stadium'
+                  )),
+    owned_card_id TEXT NOT NULL UNIQUE REFERENCES owned_cards(id) ON DELETE CASCADE,
+    updated_at    TEXT NOT NULL,
+    PRIMARY KEY (club_id, slot)
+);
+
+CREATE INDEX IF NOT EXISTS idx_club_active_items_owned
+    ON club_active_items(owned_card_id);
+
+-- Carry every existing kit designation over: 'home' -> 'home_kit',
+-- 'away' -> 'away_kit'. No designation is lost and none is invented.
+INSERT INTO club_active_items (club_id, slot, owned_card_id, updated_at)
+SELECT club_id,
+       CASE slot WHEN 'home' THEN 'home_kit' ELSE 'away_kit' END,
+       owned_card_id,
+       updated_at
+FROM club_kit_assignments
+WHERE slot IN ('home', 'away');
+
+-- 0024's trigger lives ON owned_cards, so DROP TABLE would NOT remove it and
+-- every subsequent ownership transfer would fail on a missing table. Drop it
+-- explicitly first, then replace it with the generalised one.
+DROP TRIGGER IF EXISTS clear_club_kit_assignment_before_transfer;
+DROP TABLE club_kit_assignments;
+
+CREATE TRIGGER IF NOT EXISTS clear_club_active_item_before_transfer
+BEFORE UPDATE OF club_id ON owned_cards
+WHEN OLD.club_id <> NEW.club_id
+BEGIN
+    DELETE FROM club_active_items WHERE owned_card_id = OLD.id;
+END;