修复: aichat上下文管理与信息组织P1批

逐件(证据:深查-aichat质量/信息UX-2026-10-17):
- 恢复链套娃:RECOVERY_ARTIFACT_PREFIX双侧过滤+单点拦截(E1)
- message_repo全量重写保留原created_at(E11,治1750条时间线污染)
- search_files/grep 0命中附阴性存疑提示(E6,共享negative_hit_hint)
- 项目清单三源活跃度排序+system prompt指纹对齐(E4跑题)
- 会话列表活跃/归档offset分页+侧栏加载更多(F4-1,治50硬上限)
- inject消息source标记(轮次分桶不误计发起,V52同源)
- 提示词回复风格条款中英双语(反口水话,含测试断言)
- i18n补键:复制/折叠量/发送title/历史定位提示(F1-1/F2-1/F6-1)

验收:cargo test --workspace 2281 passed 0 failed;vue-tsc EXIT 0

src/i18n/en/aiChat.ts

@@ -133,6 +133,8 @@ export default {
     queueSave: 'Save',
     queueCancel: 'Cancel',
     queueSendNow: 'Send now',
+    // UX walk panel-2 F2-1: send button title/aria (was mis-bound to queueSendNow)
+    send: 'Send',
     // 3c UX batch addition (I4 queue backfill: pull a queued item back into the input box)
     queueBackfill: 'Backfill',
 
@@ -185,6 +187,10 @@ export default {
     copyMsg: 'Copy message',
     copied: 'Copied',
     copyFailed: 'Copy failed',
+    // F1-1: code block copy button (injected at v-html render layer via decorateCodeHtml)
+    copyCode: 'Copy',
+    // F1-1: collapsed long-message summary toggle (expanded state reuses collapse key)
+    foldedSummary: '{chars} chars collapsed / ~{tokens} tokens — click to expand',
     // Copy bubble as image (html2canvas → clipboard; falls back to download)
     copyAsImage: 'Copy as image',
     copiedAsImage: 'Copied as image',
@@ -287,6 +293,8 @@ export default {
     recoverNow: 'Resume',
     viewHistory: 'View history messages',
     viewSummary: 'View context summary',
+    // UX walk panel-6 F6-1: inline hint when a history/summary jump misses (target inside a collapsed segment)
+    historyLocateInSegment: 'This message is inside a collapsed segment (archived/compressed). Expand the divider in the message flow first',
     viewContext: 'View AI context',
     contextSystemPrompt: 'System Prompt',
     contextEnvironment: 'Environment',
@@ -342,6 +350,8 @@ export default {
     editEmptyBlocked: 'Edit content is empty, submission cancelled',
     skillNoMatchQuery: 'No skill matches "{q}", send blocked',
     backfillOverwriteConfirm: 'The input box has an unsent draft; backfilling will overwrite it. Continue?',
+    // UX walk panel-2 F2-4: example-card overwrite confirm (aligned with backfill confirm)
+    exampleOverwriteConfirm: 'The input box has an unsent draft; the example will overwrite it. Continue?',
 
     // ── Outbox / scheduled messages (OutboxDrawer + ChatInput clock entry, design 2026-10-10 §3.4) ──
     outboxEntry: 'Scheduled messages',