feat(ai): 助手浮窗聚焦日志查询页,携带当前查询结果对话

- 浮球只在 /logs 渲染(产品定位:辅助分析正在查看的查询结果,其它页面不打扰)
- /logs 查询成功后写入 AI 上下文:LogQL、时间范围、结果条数、error 行数、
  最新 20 条样本(去 CRI 包装);对话请求自动携带
- 后端 /ai/chat 接收 context:截断 6000 字 + RedactTextOnly 统一脱敏后并入 system
  (ECHO 假模型实测注入完整);空态文案改为查询导向

frontend/src/pages/logs/index.tsx

@@ -18,6 +18,8 @@ import { SourcesManager } from './components/SourcesManager'
 import { LogContextDialog, type LogContext } from './components/LogContextDialog'
 import { LogResultsPanel } from './components/LogResultsPanel'
 import { literalFilters } from './query-utils'
+import { setLogsAIContext } from '@/lib/ai-assistant-context'
+import { stripLogEnvelope } from '@/lib/ingress-access-log'
 import { readQueryHistory, rememberQuery } from './query-history'
 import { useDebouncedValue } from '@/hooks/useDebouncedValue'
 
@@ -173,6 +175,14 @@ export default function LogsPage() {
       if (version !== requestVersion.current) return
       if (paging && result.entries.length === 0) { setCursor(''); return }
       if (!paging) setQueryHistory(rememberQuery(data.query))
+      // AI 助手上下文:当前查询 + 首页结果摘要(样本原文,服务端统一脱敏)
+      setLogsAIContext({
+        query: data.query,
+        rangeMinutes: Math.max(1, Math.round((r.end - r.start) / 6e10)),
+        totalEntries: result.entries.length,
+        errorLines: result.entries.filter(e => e.level === 'error').length,
+        samples: result.entries.slice(0, 20).map(e => stripLogEnvelope(e.message)),
+      })
       setExecutedQuery(data.query)
       if (!paging) setExecutedRange(r)
       setSearched(true)