新增: 仲裁合并(冲突检测+ConflictResolver+reviewer仲裁基础)

- Coordinator.merge: 跳过失败SubTask+同文件冲突检测+extract_written_files

- ConflictResolver.vue: 双栏diff展示+接受A/接受B/合并/手动按钮

- i18n: 冲突相关翻译键(中英文)

- 7个merge测试全绿(含4个新增冲突检测)

src/i18n/en/aiChat.ts

@@ -3,6 +3,11 @@ export default {
     // ── Multi-Agent parallel execution ──
     planProgress: 'Execution Plan',
     planLayer: 'Layer {n}',
+    conflictsPending: '{n} conflicts to resolve',
+    acceptA: 'Accept A',
+    acceptB: 'Accept B',
+    mergeBoth: 'Merge Both',
+    manualResolve: 'Manual',
 
     // ── Conversation sidebar ──
     sidebarTitle: 'Chats',

src/i18n/zh-CN/aiChat.ts

@@ -3,6 +3,11 @@ export default {
     // ── 多 Agent 并行执行 ──
     planProgress: '执行计划',
     planLayer: '第 {n} 层',
+    conflictsPending: '{n} 处冲突待处理',
+    acceptA: '接受 A',
+    acceptB: '接受 B',
+    mergeBoth: '合并两者',
+    manualResolve: '手动处理',
 
     // ── 对话侧栏 ──
     sidebarTitle: '对话',