feat(comparison-records): 比价记录展示 LLM 实际成本(列表列 + 详情 + 价格快照) (#47)

- 列表「成本」列优先显示后端冻结的实际成本(当时价/绿色),无则回退前端估算(灰色)
- 详情抽屉「LLM 成本」:有 llm_cost_yuan 显示实际值 +「实际·当时价」标,无则回退估算;
  另展示所用单价快照 JSON
- types.ts:ComparisonRecordListItem 加 llm_cost_yuan(详情继承)
- 顺带:InputNumber addonAfter → suffix(消 antd 弃用警告);详情 llm_calls 遍历对
  input_messages 加空值防御(残缺数据不再整页白屏)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

---------

Co-authored-by: guke <guke@autohome.com.cn>
Reviewed-on: #47

src/lib/types.ts

@@ -354,6 +354,7 @@ export interface ComparisonRecordListItem {
   retry_count: number | null;
   input_tokens: number | null;
   output_tokens: number | null;
+  llm_cost_yuan: number | null;   // 后端按「当时价」冻结的实际成本(元);旧记录 null → 「成本」列回退估算
   device_model: string | null;
   rom_vendor: string | null;
   rom_name: string | null;
@@ -396,6 +397,8 @@ export interface ComparisonRecordDetail extends ComparisonRecordListItem {
   latitude: number | null;
   llm_calls: LlmCall[] | null;
   raw_payload: Record<string, unknown> | null;
+  // 算成本所用单价快照 {mode, prices:{model:{...}}}(llm_cost_yuan 继承自列表项)。
+  llm_price_snapshot: Record<string, unknown> | null;
 }
 
 export interface AdRevenueImpression {