feat(economy): purchase_items primitive + entitlement import seeding

purchase_items: generic atomic debit + mint of several items (fail-closed) for
open-on-buy Store packs (Store BUY returns items immediately) + POST
/economy/purchase-items route. Import: add optional entitlements[] to
ProfileImportRequest, seeding unconsumed packs rows in the same transaction (so a
source's unopened packs become Core entitlements); idempotency via the existing
import fingerprint. Tests: 2 purchase_items unit + endpoint + entitlement-seed
import. Core matrix 45 lib + 116 integration + 9 import green; clippy clean.

tests/import_service_test.rs

@@ -4,8 +4,8 @@
 
 use openfut_core::services::card_db::CardDb;
 use openfut_core::services::import::{
-    apply_profile_import, ImportClub, ImportExtension, ImportOwnedCard, ImportProfile, ImportSlot,
-    ImportSquad, ProfileImportRequest,
+    apply_profile_import, ImportClub, ImportEntitlement, ImportExtension, ImportOwnedCard,
+    ImportProfile, ImportSlot, ImportSquad, ProfileImportRequest,
 };
 
 async fn fresh_pool() -> sqlx::SqlitePool {
@@ -79,6 +79,7 @@ fn request(
         },
         owned,
         squad,
+        entitlements: Vec::new(),
     }
 }
 
@@ -128,6 +129,33 @@ async fn imports_profile_club_owned_and_squad_in_one_shot() {
     assert_eq!(stored_import_fp, "fp-happy");
 }
 
+#[tokio::test]
+async fn imports_entitlements_seeds_unopened_packs() {
+    let pool = fresh_pool().await;
+    let db = CardDb::load("data").unwrap();
+    let ids = valid_ids(2);
+    let ow = owned(&ids);
+    let mut req = request("g_ent", "fp-ent", ow, None);
+    req.entitlements = vec![
+        ImportEntitlement {
+            definition_id: "70".into(),
+        },
+        ImportEntitlement {
+            definition_id: "70".into(),
+        },
+    ];
+    apply_profile_import(&pool, &db, &req)
+        .await
+        .expect("import");
+    // Two unconsumed entitlements seeded into packs (opened = 0).
+    assert_eq!(count(&pool, "packs").await, 2);
+    let unopened: i64 = sqlx::query_scalar("SELECT COUNT(*) FROM packs WHERE opened = 0")
+        .fetch_one(&pool)
+        .await
+        .unwrap();
+    assert_eq!(unopened, 2);
+}
+
 #[tokio::test]
 async fn rerun_same_fingerprint_is_idempotent_noop() {
     let pool = fresh_pool().await;