🚀 chore(ui): Refactor UpstreamRatioSync with conflict-modal component, performance hooks & cleanup (#1286)

WHAT’S NEW
• Extracted reusable ConflictConfirmModal for clearer JSX hierarchy
• Added detailed conflict detection & confirmation flow before syncing options
• Refactored state-heavy callbacks (`selectValue`, `performSync`) with `useCallback` to avoid unnecessary renders
• Introduced build-time constants (later removed unused export) and unified helper utilities
• Ensured final ratios are rebuilt accurately before API `PUT`, fixing “value not updated” bug
• Enhanced UI hints: warning icon on conflict, multiline billing info, mobile-friendly modal size
• General code cleanup: removed dead variables, adopted early returns, improved comments

WHY
Improves maintainability, user clarity when billing-type collisions occur, and guarantees data consistency after synchronisation.

web/src/i18n/locales/en.json

@@ -1728,5 +1728,9 @@
   "自适应列表": "Adaptive list",
   "紧凑列表": "Compact list",
   "仅显示矛盾倍率": "Only show conflicting ratios",
-  "矛盾": "Conflict"
+  "矛盾": "Conflict",
+  "确认冲突项修改": "Confirm conflict item modification",
+  "该模型存在固定价格与倍率计费方式冲突，请确认选择": "The model has a fixed price and ratio billing method conflict, please confirm the selection",
+  "当前计费": "Current billing",
+  "修改为": "Modify to"
 }