Remove the per-row delete button from Explore's cards

Matches KanbanCard, which never had one -- deleting a card lives on
its own view now (CardManageMenu's "Delete card"), reachable by
clicking through from either list.

Cleaned up what that leaves unused: the cards store's remove() (its
only caller), and .card-row__delete's styling.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

web/src/stores/cards.ts

@@ -56,11 +56,6 @@ export const useCardsStore = defineStore('cards', () => {
 
   const setComplete = (card: Card, complete: boolean) => patch(card, { complete })
 
-  async function remove(card: Card): Promise<void> {
-    await apiRequest(`/cards/${card.id}`, { method: 'DELETE', auth: true })
-    cards.value = cards.value.filter((c) => c.id !== card.id)
-  }
-
   function reset(): void {
     cards.value = []
     projectId.value = null
@@ -76,7 +71,6 @@ export const useCardsStore = defineStore('cards', () => {
     load,
     add,
     setComplete,
-    remove,
     reset,
   }
 })