fifa17 store: real 6-pack economy + full-DB pool; drop extPrice

- store_catalog: replace the invented catalogue with the real always-available
  FUT17 regular packs (Bronze/Prem Bronze/Silver/Prem Silver/Gold/Prem Gold) at
  real prices + tier composition; PackDef now carries per-tier quantities.
- pack_body: drop extPrice (its mtx side-effect switched on the broken "or %1s"
  FIFA-Points tile line; plan-2026-08-05-store-subsystem.md section 3.4).
- pack_content: tier-aware generator draws each pack bronze/silver/gold
  composition with special_chance bias + empty-tier fallback.
- host: CoreAccess::all_definitions (GET /cards); build_content_pool draws the
  FULL card universe via non-minting catalog lookup, owned-inventory fallback.
- economy_differential: store ops reclassified DIFFERENT-BY-DESIGN (Rust is the
  authoritative store; Python oracle stays the untouched rollback baseline).
- fixtures/tests updated to the real catalogue.

Odds are DESIGNED placeholders (FUT17 pack probabilities were never published);
club items remain excluded (cardtype-9 mapping unknown). Full regression green;
real prices + tier-correct draws verified server-side on staging.

openfut-utas-host/tests/economy_concurrency.rs

@@ -311,7 +311,7 @@ fn case_a_two_buys(h: &Harness) -> String {
             refs, 1,
             "exactly one BUY refused 461 (statuses {statuses:?})"
         );
-        // The winner minted 5 cards; the loser minted nothing.
+        // The winner minted 12 cards (real Bronze Pack); the loser minted nothing.
         for r in &rs {
             if r.status == 200 {
                 assert_eq!(
@@ -319,7 +319,7 @@ fn case_a_two_buys(h: &Harness) -> String {
                         .as_array()
                         .unwrap()
                         .len(),
-                    5
+                    12
                 );
             }
         }