feat(app): 接入 AKShare 行情采集、净值查询与前端净值曲线

[变更性质]
- 本提交完成 3b 行情闭环：真实 AKShare 搜索与净值采集、PostgreSQL 持久化、鉴权 API 与 Fable 前端净值曲线展示。

[新增功能]
- API 新增 /api/instruments/search、/api/instruments/{code}/nav 与 nav/refresh 接口，经 Bearer 鉴权调用 AKShare Python 采集器并幂等落库。
- 前端提供基金搜索、精确代码选择、历史净值刷新/重读与 SVG 折线图，token 变更即清空私有结果并失效在途请求。

[实现方案]
- MarketData 以 requiredProperty 校验采集器 payload，净值观测按 (code, nav_date) 幂等 upsert 并保留来源与哈希。
- 前端以 requestId 序列守卫 SearchCompleted/SearchFailed/NavCompleted/NavFailed，TokenChanged 同时递增 searchSeq/navSeq 拒绝过期响应；边界解码兼容 F# option 的 {"case":"Some"} 线格式。

[影响范围]
- 新增 FundLab.Web.Tests（边界解码、序列失效、图表纯函数共 8 项），扩展 API 测试至 20 项；vite dev 代理 /api 至本地 API。
- 真实 AKShare 端到端依赖本机 akshare 环境，由负责人另行验收；本提交不包含 docs/overnight-progress.md 的现有修改。

1 files changed, 66 insertions, 0 deletions

diff --git a/tests/FundLab.Api.Tests/ApiTests.fs b/tests/FundLab.Api.Tests/ApiTests.fs
index a46d330..1aaab6b 100644
--- a/tests/FundLab.Api.Tests/ApiTests.fs
+++ b/tests/FundLab.Api.Tests/ApiTests.fs
@@ -2,6 +2,7 @@ namespace FundLab.Api.Tests
 
 module ApiTests =
 
+    open System
     open Xunit
     open FundLab.Api
 
@@ -22,3 +23,68 @@ module ApiTests =
 
         Assert.Contains("\"status\":\"ok\"", payload)
         Assert.DoesNotContain("secret", payload)
+
+    [<Fact>]
+    let ``AKShare NAV payload keeps missing publication time empty`` () =
+        let payload =
+            """
+            {
+              "schema_version": "fund-lab.akshare.v1",
+              "operation": "nav",
+              "source": "akshare",
+              "source_revision": "akshare-1.18.96/eastmoney",
+              "collected_at": "2026-09-21T10:00:00Z",
+              "instrument": { "code": "000001" },
+              "observations": [
+                {
+                  "nav_date": "2001-12-18",
+                  "published_at": null,
+                  "nav": "1.00000000",
+                  "accumulated_nav": null,
+                  "daily_return": "0.00"
+                }
+              ]
+            }
+            """
+
+        match MarketData.parseNavPayload payload with
+        | Ok parsed ->
+            let observation = parsed.Observations |> List.head
+            Assert.Equal("000001", parsed.Code)
+            Assert.Equal(DateOnly(2001, 12, 18), observation.NavDate)
+            Assert.Equal(None, observation.PublishedAt)
+            Assert.Equal(None, observation.AccumulatedNav)
+            Assert.Equal(Some 0.00m, observation.DailyReturn)
+            Assert.Equal(1.00000000m, observation.Nav)
+        | Error message ->
+            Assert.Fail(sprintf "expected valid NAV payload, got %s" message)
+
+    [<Fact>]
+    let ``AKShare search payload preserves exact fund code and source`` () =
+        let payload =
+            """
+            {
+              "schema_version": "fund-lab.akshare.v1",
+              "operation": "search",
+              "source": "akshare",
+              "source_revision": "akshare-1.18.96/eastmoney",
+              "collected_at": "2026-09-21T10:00:00Z",
+              "instruments": [
+                {
+                  "code": "000001",
+                  "name": "华夏成长混合",
+                  "fund_type": "混合型-灵活"
+                }
+              ]
+            }
+            """
+
+        match MarketData.parseSearchPayload payload with
+        | Ok parsed ->
+            let instrument = parsed.Instruments |> List.head
+            Assert.Equal("000001", instrument.Code)
+            Assert.Equal("华夏成长混合", instrument.Name)
+            Assert.Equal(Some "混合型-灵活", instrument.FundType)
+            Assert.Equal("akshare", parsed.Source)
+        | Error message ->
+            Assert.Fail(sprintf "expected valid search payload, got %s" message)