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, 181 insertions, 0 deletions

diff --git a/src/FundLab.Api/MarketDataService.fs b/src/FundLab.Api/MarketDataService.fs
new file mode 100644
index 0000000..8047071
--- /dev/null
+++ b/src/FundLab.Api/MarketDataService.fs
@@ -0,0 +1,181 @@
+namespace FundLab.Api
+
+open System
+open System.Diagnostics
+open System.IO
+open System.Security.Cryptography
+open System.Text
+
+type MarketDataFailure =
+    | InvalidMarketDataRequest of string
+    | MarketDataCollectorUnavailable of string
+    | InvalidMarketDataPayload of string
+    | MarketDataPersistenceFailure of string
+
+type IMarketDataCollector =
+    abstract Search: query: string -> Result<string, string>
+    abstract FetchNav: code: string -> Result<string, string>
+
+type IMarketDataService =
+    abstract Search: query: string -> Result<MarketDataSearchPayload, MarketDataFailure>
+    abstract RefreshNav: code: string -> Result<MarketDataNavRecord list, MarketDataFailure>
+    abstract GetNav: code: string * fromDate: DateOnly option * toDate: DateOnly option -> Result<MarketDataNavRecord list, MarketDataFailure>
+
+type ProcessMarketDataCollector(pythonExecutable: string, scriptPath: string, pythonPath: string option) =
+    let execute arguments =
+        if not (File.Exists scriptPath) then
+            Error(sprintf "collector script was not found at %s" scriptPath)
+        else
+            let startInfo = ProcessStartInfo()
+            startInfo.FileName <- pythonExecutable
+            startInfo.UseShellExecute <- false
+            startInfo.RedirectStandardOutput <- true
+            startInfo.RedirectStandardError <- true
+            startInfo.WorkingDirectory <- Path.GetDirectoryName(scriptPath)
+
+            startInfo.ArgumentList.Add(scriptPath)
+
+            for argument in arguments do
+                startInfo.ArgumentList.Add(argument)
+
+            match pythonPath with
+            | Some value -> startInfo.Environment["PYTHONPATH"] <- value
+            | None -> ()
+
+            use child = new Process()
+            child.StartInfo <- startInfo
+
+            try
+                if not (child.Start()) then
+                    Error "could not start the AKShare collector"
+                else
+                    let output = child.StandardOutput.ReadToEnd()
+                    let error = child.StandardError.ReadToEnd()
+                    child.WaitForExit()
+
+                    if child.ExitCode = 0 && not (String.IsNullOrWhiteSpace output) then
+                        Ok output
+                    elif String.IsNullOrWhiteSpace error then
+                        Error(sprintf "collector exited with code %d" child.ExitCode)
+                    else
+                        Error(error.Trim())
+            with error ->
+                Error(error.Message)
+
+    static member FromEnvironment() =
+        let value name fallback =
+            Environment.GetEnvironmentVariable(name)
+            |> Option.ofObj
+            |> Option.filter (String.IsNullOrWhiteSpace >> not)
+            |> Option.defaultValue fallback
+
+        let python = value "FUND_LAB_AKSHARE_PYTHON" "python3"
+        let script = Path.Combine(AppContext.BaseDirectory, "akshare_collector.py")
+
+        let pythonPath =
+            Environment.GetEnvironmentVariable("FUND_LAB_AKSHARE_PYTHONPATH")
+            |> Option.ofObj
+            |> Option.filter (String.IsNullOrWhiteSpace >> not)
+
+        ProcessMarketDataCollector(python, script, pythonPath)
+
+    interface IMarketDataCollector with
+        member _.Search(query: string) =
+            execute [ "--operation"; "search"; "--query"; query ]
+
+        member _.FetchNav(code: string) =
+            execute [ "--operation"; "nav"; "--code"; code ]
+
+type MarketDataService(repository: FundRepository, collector: IMarketDataCollector) =
+    let codePattern = Text.RegularExpressions.Regex("^[0-9]{6}$", Text.RegularExpressions.RegexOptions.Compiled)
+
+    let payloadHash (raw: string) =
+        Convert.ToHexString(SHA256.HashData(Encoding.UTF8.GetBytes(raw)))
+
+    let collectorFailure error = MarketDataCollectorUnavailable error
+    let payloadFailure error = InvalidMarketDataPayload error
+
+    let parseSearch raw =
+        match MarketData.parseSearchPayload raw with
+        | Ok payload -> Ok(payload, payloadHash raw)
+        | Error message -> Error(payloadFailure message)
+
+    let parseNav raw =
+        match MarketData.parseNavPayload raw with
+        | Ok payload -> Ok(payload, payloadHash raw)
+        | Error message -> Error(payloadFailure message)
+
+    let persistSearch (payload: MarketDataSearchPayload) hash =
+        try
+            repository.UpsertInstruments(payload, hash)
+            Ok payload
+        with error ->
+            Error(MarketDataPersistenceFailure error.Message)
+
+    let persistNav (payload: MarketDataNavPayload) hash =
+        try
+            repository.UpsertNavObservations(payload, hash)
+            Ok(repository.GetNav(payload.Code, None, None))
+        with error ->
+            Error(MarketDataPersistenceFailure error.Message)
+
+    let validCode code =
+        not (String.IsNullOrWhiteSpace code) && codePattern.IsMatch(code)
+
+    member _.Search(query: string) =
+        let normalizedQuery = if isNull query then "" else query.Trim()
+
+        if String.IsNullOrWhiteSpace normalizedQuery || normalizedQuery.Length > 80 then
+            Error(InvalidMarketDataRequest "search query must contain 1 to 80 characters")
+        else
+            match collector.Search normalizedQuery with
+            | Error message -> Error(collectorFailure message)
+            | Ok raw ->
+                match parseSearch raw with
+                | Error failure -> Error failure
+                | Ok(payload, hash) -> persistSearch payload hash
+
+    member _.RefreshNav(code: string) =
+        let normalizedCode = if isNull code then "" else code.Trim()
+
+        if not (validCode normalizedCode) then
+            Error(InvalidMarketDataRequest "fund code must contain exactly six digits")
+        else
+            match collector.Search normalizedCode with
+            | Error message -> Error(collectorFailure message)
+            | Ok searchRaw ->
+                match parseSearch searchRaw with
+                | Error failure -> Error failure
+                | Ok(searchPayload, searchHash) ->
+                    match searchPayload.Instruments |> List.tryFind (fun instrument -> instrument.Code = normalizedCode) with
+                    | None -> Error(InvalidMarketDataRequest "fund code was not found in the source catalog")
+                    | Some _ ->
+                        match persistSearch searchPayload searchHash with
+                        | Error failure -> Error failure
+                        | Ok _ ->
+                            match collector.FetchNav normalizedCode with
+                            | Error message -> Error(collectorFailure message)
+                            | Ok navRaw ->
+                                match parseNav navRaw with
+                                | Error failure -> Error failure
+                                | Ok(navPayload, navHash) when navPayload.Code <> normalizedCode ->
+                                    Error(payloadFailure "NAV payload code does not match the requested fund code")
+                                | Ok(navPayload, navHash) -> persistNav navPayload navHash
+
+    member _.GetNav(code: string, fromDate: DateOnly option, toDate: DateOnly option) =
+        let normalizedCode = if isNull code then "" else code.Trim()
+
+        if not (validCode normalizedCode) then
+            Error(InvalidMarketDataRequest "fund code must contain exactly six digits")
+        elif fromDate.IsSome && toDate.IsSome && fromDate.Value > toDate.Value then
+            Error(InvalidMarketDataRequest "from date must not be after to date")
+        else
+            try
+                Ok(repository.GetNav(normalizedCode, fromDate, toDate))
+            with error ->
+                Error(MarketDataPersistenceFailure error.Message)
+
+    interface IMarketDataService with
+        member this.Search(query) = this.Search(query)
+        member this.RefreshNav(code) = this.RefreshNav(code)
+        member this.GetNav(code, fromDate, toDate) = this.GetNav(code, fromDate, toDate)