Sea Select FLIP: source the card-back from the seat's deck, not equipped_deck — TDD

The sea-stage FLIP no-op'd in the gameroom because `_sea_stage.html` rendered
the back-img from `request.user.equipped_deck.back_image_url` — but
`select_role` NULLS OUT the user's equipped_deck once it's contributed to the
room's seats (views.py:1148), so in the Sea Select phase the deck was None →
no back-img element → sea.js's FLIP handler short-circuits on the missing
`.sig-stage-card-back-img` sibling. (my_sea worked: solo, no contribution.)

- `_sea_stage.html` now renders the back-img from a `sea_back_image_url` ctx var
  instead of `request.user.equipped_deck`
- gameroom: `_role_select_context` sets it from the SEAT's contributed deck
  (`_canonical_seat.deck_variant`, when it has card images)
- my_sea: the my_sea view sets it from the user's own equipped deck
- ITs: image seat-deck renders `.sig-stage-card-back-img`; text seat-deck omits it

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/apps/epic/tests/integrated/test_views.py

@@ -4162,19 +4162,24 @@ class PickSeaUnifiedFeltTest(TestCase):
         content = self.client.get(self.url).content.decode()
         self.assertIn("room-menu-sea", content)
 
-    def test_sea_stage_renders_back_img_for_image_deck(self):
-        """The sea-stage FLIP reveals the card back. The back-img now renders for
-        ANY image-equipped deck WITH a back image (polarized or not) — dropping
-        the old `not is_polarized` gate — so the Gravity/Levity draw can show a
-        polarity-tinted back (user-spec 2026-06-07)."""
+    def test_sea_stage_renders_back_img_from_seat_deck(self):
+        """The sea-stage FLIP reveals the card back. The back-img is sourced from
+        the SEAT's contributed deck (NOT request.user.equipped_deck, which
+        select_role nulls out → the back silently never rendered + FLIP no-op'd)
+        and renders for any image-equipped deck w. a back (user-flagged
+        2026-06-07)."""
         minch = DeckVariant.objects.get(slug="minchiate-fiorentine-1860-1890")
-        founder = self.gamers[0]
-        founder.unlocked_decks.add(minch)
-        founder.equipped_deck = minch
-        founder.save(update_fields=["equipped_deck"])
+        self.pc_seat.deck_variant = minch
+        self.pc_seat.save(update_fields=["deck_variant"])
         content = self.client.get(self.url).content.decode()
         self.assertIn("sig-stage-card-back-img", content)
 
+    def test_sea_stage_no_back_img_for_text_seat_deck(self):
+        """Earthman (text-mode, no card images) → no back-img element (FLIP is a
+        no-op for text decks, by design)."""
+        content = self.client.get(self.url).content.decode()
+        self.assertNotIn("sig-stage-card-back-img", content)
+
     def test_always_two_deck_stacks_gravity_and_levity(self):
         """Unlike my_sea / Sig Select, the room Sea Select ALWAYS shows BOTH the
         Gravity + Levity stacks — the gamer draws from either populated half

src/apps/epic/views.py

@@ -680,6 +680,15 @@ def _role_select_context(room, user, seat_param=None):
             )
             # 6-card Celtic Cross is complete at 6 placed cards.
             ctx["hand_complete"] = len(_sea_hand) >= 6
+            # Sea-stage FLIP card-back — sourced from the SEAT's contributed deck,
+            # NOT request.user.equipped_deck (which `select_role` nulls out once
+            # the deck is contributed to the room → the back-img silently never
+            # rendered in the gameroom + FLIP no-op'd). User-flagged 2026-06-07.
+            _back_deck = _canonical_seat.deck_variant if _canonical_seat else None
+            ctx["sea_back_image_url"] = (
+                _back_deck.back_image_url
+                if (_back_deck and _back_deck.has_card_images) else ""
+            )
 
     return ctx
 

src/apps/gameboard/views.py

@@ -372,6 +372,14 @@ def my_sea(request):
         "significator_reversed": sig_reversed,
         "default_spread": default_spread,
         "reversals_pct": 25,
+        # Sea-stage FLIP card-back — my_sea is solo (no deck contribution), so the
+        # user's OWN equipped deck is the right source (the gameroom uses the
+        # seat's contributed deck instead; see _sea_stage.html).
+        "sea_back_image_url": (
+            request.user.equipped_deck.back_image_url
+            if (request.user.equipped_deck and request.user.equipped_deck.has_card_images)
+            else ""
+        ),
         "sea_deck_data": (
             _my_sea_deck_data(request.user, exclude_id=sig_card.id if sig_card else None)
             if user_has_sig else {"levity": [], "gravity": []}

src/templates/apps/gameboard/_partials/_sea_stage.html

@@ -43,20 +43,19 @@
             </div>
             {% comment %}
             back-img + FLIP btn. FLIP reveals the card back. Renders for ANY
-            image-equipped deck that has a back image — INCLUDING polarized decks
+            image-equipped deck w. a back image — INCLUDING polarized decks
             (user-spec 2026-06-07): the Sea Select phase tints the back per the
             drawn card's polarity (`.sea-stage--gravity` / `--levity`, see
             `_card-deck.scss`), so the same back-art reads distinctly for the two
-            stacks (was previously gated to non-polarized decks, where it never
-            rendered for the room's Gravity/Levity draw). The FLIP btn renders
-            unconditionally; sea.js's handler no-ops when no back-img sibling
-            exists (text decks). Multi-user gameroom limitation: the src is the
-            VIEWER's deck-back — correct for the sea (each gamer draws their own),
-            parked for the general multi-user case.
+            stacks. `sea_back_image_url` is set by each caller from the RIGHT
+            deck: the gameroom uses the SEAT's contributed deck (NOT
+            request.user.equipped_deck, which select_role nulls out → the back
+            silently never rendered + FLIP no-op'd); my_sea uses the user's
+            equipped deck. FLIP btn renders unconditionally; sea.js's handler
+            no-ops when no back-img sibling exists (text decks).
             {% endcomment %}
-            {% if request.user.is_authenticated and request.user.equipped_deck.has_card_images and request.user.equipped_deck.back_image_url %}
-            <img class="sig-stage-card-back-img" alt=""
-                 src="{{ request.user.equipped_deck.back_image_url }}">
+            {% if sea_back_image_url %}
+            <img class="sig-stage-card-back-img" alt="" src="{{ sea_back_image_url }}">
             {% endif %}
             <button class="btn btn-reveal sea-stage-flip-btn" type="button" aria-label="Flip card">FLIP</button>
         </div>