feat(pokemon): enforce bidirectional opposite sync and hide opposite text

Add unique indexes and transactional sync for opposite configurations
Remove explicit opposite names and labels from Pokemon detail view

system-wordings.ts

@@ -597,7 +597,6 @@ export const systemWordingMessages = {
         skillsCoreNote: 'Affects habitat selection, item drops, and Trading behavior.',
         environmentCoreNote: 'Affects habitat selection and related Pokemon comparison.',
         favoriteThingsCoreNote: 'Affects item drops, hidden item tags, and Trading price evidence.',
-        opposite: 'Opposite',
         genus: 'Genus',
         height: 'Height',
         heightInput: 'Height (in)',
@@ -2022,7 +2021,6 @@ export const systemWordingMessages = {
         skillsCoreNote: '影响栖息地选择、物品掉落和 Trading 行为。',
         environmentCoreNote: '影响栖息地选择和相关 Pokemon 对比。',
         favoriteThingsCoreNote: '影响物品掉落、隐藏标签判断和 Trading 价格证据。',
-        opposite: '反义',
         genus: '分类',
         height: '身高',
         heightInput: '身高（in）',