fix(fifa17): keep empty My Packs group client-safe

When the account owns zero unopened packs, store_catalog() emits a synthetic `mypacks` group placeholder (id 65534, absent from PACK_CATALOG). Change its state from "inactive" to "active".

Root cause (bug 6c): FIFA 17's Store/Scaleform path resolves the `mypacks` category even with zero unopened packs (category chosen client-side via the movie's CATEGORY_ID -> screen+0x290; no server field gates it). CardsDLL FUN_1800147f0 then dereferences the resolved group with no null guard, so an absent group crashes the client (CardsDLL+0x14882, [NULL+0x48], minidump-confirmed). An inactive placeholder avoids the crash but makes the Store report the pack unavailable on entry and bounce to the Hub; an active placeholder lets the Store open normally.

65534 stays economy-safe: pack_by_id() returns None, so store_buy()/purchased_items() cannot open it or grant items/coins, and grant_unopened_pack() rejects it. Explicit selection is rejected client-side ("This pack is no longer available") and sends no backend request. This is a FIFA-17 client-compatibility shim (P2), not an EA-authentic representation, confined to the FIFA-17 backend (not OpenFUT Core). A clean zero-pack UX needs a client-side fix (docs/plans/FIFA17_EMPTY_MYPACKS_CLIENT_FIX.md).

Adds regression tests (test_empty_mypacks.py): empty -> one active 65534 placeholder (absent from PACK_CATALOG); non-empty [70] -> no placeholder, genuine pack shown; economy safety; normal packs 1/5/6/7 untouched.

fifa17-recon/tools/utas_server.py

@@ -3426,12 +3426,31 @@ def store_catalog(h):
         if owned:
             packs.append(_pack_body(owned, idx, owned=True))
     if not owned_ids:
-        # GOTO_STORE_MYPACK resolves the hard-coded `mypacks` group before it
-        # renders rows.  If the group is absent FIFA falls back to Bronze and
-        # shows the empty-category dialog over the wrong tab.  Retain an inactive
-        # zero-item sentinel so the destination resolves, while state != active
-        # keeps it out of the visible row list.  Its id is deliberately absent
-        # from PACK_CATALOG, so both purchase/open handlers reject it as well.
+        # EMPTY MY PACKS -- FIFA 17 client-compatibility workaround (bug 6c, P2).
+        #
+        # The Store/Scaleform path RESOLVES the `mypacks` category even when the
+        # account owns zero unopened packs (the category is chosen client-side from
+        # the movie's CATEGORY_ID -> screen+0x290; no server field gates it).
+        # CardsDLL FUN_1800147f0 then dereferences the resolved group with NO null
+        # guard, so if no `mypacks` group exists the client CRASHES
+        # (CardsDLL_Win64_retail.dll+0x14882, read of [NULL+0x48] -- confirmed by
+        # minidump). We therefore MUST emit a `mypacks` group when empty.
+        #
+        # state="inactive" avoids the crash but makes the client report the pack
+        # unavailable immediately on Store entry and bounce to the Hub. state="active"
+        # keeps the group structurally valid AND lets the Store open normally; the
+        # empty tile renders as "0 items" and an explicit open is rejected
+        # CLIENT-SIDE ("This pack is no longer available") -- it sends NO backend
+        # request and mutates nothing.
+        #
+        # id 65534 is deliberately ABSENT from PACK_CATALOG, so pack_by_id() returns
+        # None and store_buy()/purchased_items() cannot open it, grant items/coins,
+        # or add it to unopenedPackIds. This is a compatibility shim for FIFA 17
+        # client behavior, NOT an EA-authentic empty-My-Packs representation, and it
+        # is FIFA17-specific (do not lift into game-independent Core). A fully clean
+        # zero-pack UX requires a client-side fix -- see
+        # docs/plans/FIFA17_EMPTY_MYPACKS_CLIENT_FIX.md and the evidence in
+        # docs/evidence/STORE_TILE_6C.md / FIFA17_EMPTY_MYPACKS_CLIENT_CONTRACT.md.
         sentinel = {
             "id": 65534,
             "name": "",
@@ -3441,7 +3460,7 @@ def store_catalog(h):
             "specialChance": 0.0,
         }
         empty = _pack_body(sentinel, 1, owned=True)
-        empty["state"] = "inactive"
+        empty["state"] = "active"
         empty["unopened"] = False
         packs.append(empty)
     return 200, {"purchase": packs, "timestamp": 1596326400}