COIN: unequip on deposit (parity w. CARTE) ; fix FT false-positive masking the bug

User reported on iPhone: after depositing a COIN at a game's gatekeeper, the Kit Bag's Trinket slot still shows the COIN — even though the tooltip correctly carries the room attribution ("Ready 2026-05-25 / Billingsworth"). Expected behavior matches CARTE: the deposited token disappears from the Kit Bag Trinket slot because it's committed elsewhere & can't be re-used as the active trinket until released. PASS preserved — auto-admits w.o ever going thru the deposit path so it stays equipped ; **the real bug**: `debit_token` in epic/models.py's COIN branch set `current_room` + `next_ready_at` but never cleared `user.equipped_trinket`. CARTE's `drop_token` view (epic/views.py:440-442) explicitly unequips at deposit time via `user.equipped_trinket = None; user.save(update_fields=["equipped_trinket"])`; COIN had no parity. Fix: same 4-line unequip stanza now lives inside the COIN branch of `debit_token`, guarded by `if user.equipped_trinket_id == token.pk` so a fresh-purchased COIN deposit (not the equipped one) doesn't accidentally clear another trinket. PASS untouched — falls thru `debit_token` w.o entering any branch & never reaches this path; CARTE untouched too (its branch is `pass`, unequip happens at `drop_token` time before debit_token is even called) ; **the FT false-positive**: yesterday's Sprint 2 commit (d2491c5) shipped `test_coin_deposit_unequips_from_kit_bag_and_fills_one_slot` w. selector `#id_kit_bag_dialog .kit-bag-placeholder`. That selector was matching the **Dice** section's placeholder (Dice feature isn't built — `_kit_bag_panel.html` L23-29 renders `.kit-bag-placeholder` unconditionally), masking the bug whether or not the Trinket section was empty. Tightened to `.kit-bag-section--trinket .kit-bag-placeholder` w. comment explaining why a bare selector is unsafe ; template change in `_kit_bag_panel.html` L31: Trinket section gains a `kit-bag-section--trinket` modifier class so the FT (and any future selector that needs to single out the trinket section vs the deck/dice/tokens siblings) has an anchor. Mirrors the existing `kit-bag-section--tokens` class at L70 ; TDD trail: (1) tightened selector + reran → red on `NoSuchElement` (no `.kit-bag-section--trinket .kit-bag-placeholder` because COIN still equipped post-deposit, so trinket section renders the token card not the placeholder); (2) added unequip stanza to debit_token; (3) reran → green. 10 trinket FTs in 99s; 999 IT/UT in 46s — no regressions ; **generalizable trap**: when an FT waits for an element via a CSS selector, scope the selector to the section/container that uniquely identifies the assertion target — a class like `.kit-bag-placeholder` that's reused across multiple sections will silently pass even when the section you care about is in the wrong state. This is the second false-positive trap in two days (cf. d2491c5's wrong-selector trap where `.token-slot.claimed` was Carte-specific); pattern's worth noting

Code architected by Disco DeDisco <discodedisco@outlook.com>
Git commit message Co-Authored-By:
Claude Sonnet 4.6 <noreply@anthropic.com>

src/templates/core/_partials/_kit_bag_panel.html

@@ -28,7 +28,7 @@
     </div>
 </div>
 
-<div class="kit-bag-section">
+<div class="kit-bag-section kit-bag-section--trinket">
     <span class="kit-bag-label">Trinket</span>
     <div class="kit-bag-row">
         {% if equipped_trinket %}