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, 294 insertions, 0 deletions

diff --git a/src/FundLab.Api/MarketData.fs b/src/FundLab.Api/MarketData.fs
new file mode 100644
index 0000000..e396a7d
--- /dev/null
+++ b/src/FundLab.Api/MarketData.fs
@@ -0,0 +1,294 @@
+namespace FundLab.Api
+
+open System
+open System.Globalization
+open System.Text.Json
+
+type MarketDataInstrument =
+    {
+        Code: string
+        Name: string
+        FundType: string option
+    }
+
+type MarketDataObservation =
+    {
+        NavDate: DateOnly
+        PublishedAt: DateTimeOffset option
+        Nav: decimal
+        AccumulatedNav: decimal option
+        DailyReturn: decimal option
+    }
+
+type MarketDataSearchPayload =
+    {
+        Source: string
+        SourceRevision: string
+        CollectedAt: DateTimeOffset
+        Instruments: MarketDataInstrument list
+    }
+
+type MarketDataNavPayload =
+    {
+        Source: string
+        SourceRevision: string
+        CollectedAt: DateTimeOffset
+        Code: string
+        Observations: MarketDataObservation list
+    }
+
+type MarketDataInstrumentRecord =
+    {
+        Code: string
+        Name: string
+        FundType: string option
+        Source: string
+        SourceRevision: string
+        SourceCollectedAt: DateTimeOffset
+        SourcePayloadHash: string
+        FirstSeenAt: DateTimeOffset
+        LastSeenAt: DateTimeOffset
+    }
+
+type MarketDataNavRecord =
+    {
+        Code: string
+        NavDate: DateOnly
+        PublishedAt: DateTimeOffset option
+        Nav: decimal
+        AccumulatedNav: decimal option
+        DailyReturn: decimal option
+        Source: string
+        SourceRevision: string
+        SourceCollectedAt: DateTimeOffset
+        SourcePayloadHash: string
+        FirstSeenAt: DateTimeOffset
+        LastSeenAt: DateTimeOffset
+    }
+
+module MarketData =
+    type private ResultBuilder() =
+        member _.Bind(value, binder) = Result.bind binder value
+        member _.Return(value) = Ok value
+        member _.ReturnFrom(value) = value
+        member _.Zero() : Result<unit, string> = Ok ()
+        member _.Combine(first: Result<unit, string>, second: unit -> Result<'a, string>) =
+            match first with
+            | Ok () -> second ()
+            | Error message -> Error message
+        member _.Delay(generator: unit -> Result<'a, string>) = generator
+        member _.Run(generator: unit -> Result<'a, string>) = generator ()
+
+    let private result = ResultBuilder()
+    let private invariant = CultureInfo.InvariantCulture
+
+    let private requiredProperty (root: JsonElement) (name: string) =
+        let mutable property = Unchecked.defaultof<JsonElement>
+
+        if root.ValueKind <> JsonValueKind.Object then
+            Error "payload root must be a JSON object"
+        elif root.TryGetProperty(name, &property) then
+            Ok property
+        else
+            Error(sprintf "payload property '%s' is required" name)
+
+    let private requiredString (root: JsonElement) name =
+        requiredProperty root name
+        |> Result.bind (fun property ->
+            if property.ValueKind = JsonValueKind.String then
+                let value = property.GetString()
+
+                if String.IsNullOrWhiteSpace value then
+                    Error(sprintf "payload property '%s' must not be empty" name)
+                else
+                    Ok value
+            else
+                Error(sprintf "payload property '%s' must be a string" name))
+
+    let private optionalString (root: JsonElement) name =
+        requiredProperty root name
+        |> Result.bind (fun property ->
+            if property.ValueKind = JsonValueKind.Null then
+                Ok None
+            elif property.ValueKind = JsonValueKind.String then
+                let value = property.GetString()
+
+                if String.IsNullOrWhiteSpace value then
+                    Ok None
+                else
+                    Ok(Some value)
+            else
+                Error(sprintf "payload property '%s' must be null or a string" name))
+
+    let private validateEnvelope root operation =
+        result {
+            let! schemaVersion = requiredString root "schema_version"
+            let! actualOperation = requiredString root "operation"
+            let! source = requiredString root "source"
+            let! sourceRevision = requiredString root "source_revision"
+            let! collectedAtText = requiredString root "collected_at"
+
+            if schemaVersion <> "fund-lab.akshare.v1" then
+                return! Error(sprintf "unsupported schema_version '%s'" schemaVersion)
+
+            if actualOperation <> operation then
+                return! Error(sprintf "payload operation must be '%s'" operation)
+
+            match DateTimeOffset.TryParse(collectedAtText, invariant, DateTimeStyles.RoundtripKind) with
+            | true, collectedAt ->
+                return source, sourceRevision, collectedAt
+            | false, _ ->
+                return! Error "collected_at must be an ISO-8601 timestamp"
+        }
+
+    let private isFundCode (value: string) =
+        value.Length = 6 && value |> Seq.forall Char.IsDigit
+
+    let private parseFundCode root =
+        requiredString root "code"
+        |> Result.bind (fun code ->
+            if isFundCode code then
+                Ok code
+            else
+                Error "fund code must contain exactly six digits")
+
+    let private parseDate text =
+        let mutable date = DateOnly.MinValue
+
+        if DateOnly.TryParseExact(text, "yyyy-MM-dd", invariant, DateTimeStyles.None, &date) then
+            Ok date
+        else
+            Error "nav_date must be an ISO date"
+
+    let private parseDecimal label (property: JsonElement) =
+        if property.ValueKind <> JsonValueKind.String then
+            Error(sprintf "%s must be a decimal string" label)
+        else
+            let text = property.GetString()
+
+            if not (String.IsNullOrWhiteSpace text) then
+                match Decimal.TryParse(text, NumberStyles.AllowLeadingSign ||| NumberStyles.AllowDecimalPoint, invariant) with
+                | true, value -> Ok value
+                | false, _ -> Error(sprintf "%s must be a decimal string" label)
+            else
+                Error(sprintf "%s must be a decimal string" label)
+
+    let private optionalDecimal label (property: JsonElement) =
+        if property.ValueKind = JsonValueKind.Null then
+            Ok None
+        else
+            parseDecimal label property |> Result.map Some
+
+    let private optionalPublishedAt (property: JsonElement) =
+        if property.ValueKind = JsonValueKind.Null then
+            Ok None
+        elif property.ValueKind <> JsonValueKind.String then
+            Error "published_at must be null or an ISO-8601 timestamp"
+        else
+            let text = property.GetString()
+
+            if String.IsNullOrWhiteSpace text then
+                Error "published_at must be null or an ISO-8601 timestamp"
+            else
+                match DateTimeOffset.TryParse(text, invariant, DateTimeStyles.RoundtripKind) with
+                | true, value -> Ok(Some value)
+                | false, _ -> Error "published_at must be null or an ISO-8601 timestamp"
+
+    let private parseArray parser (property: JsonElement) =
+        if property.ValueKind <> JsonValueKind.Array then
+            Error "payload collection must be a JSON array"
+        else
+            property.EnumerateArray()
+            |> Seq.fold
+                (fun state item ->
+                    match state, parser item with
+                    | Ok values, Ok value -> Ok(value :: values)
+                    | Error message, _ -> Error message
+                    | _, Error message -> Error message)
+                (Ok [])
+            |> Result.map List.rev
+
+    let private parseSearchInstrument root =
+        result {
+            let! code = parseFundCode root
+            let! name = requiredString root "name"
+            let! fundType = optionalString root "fund_type"
+
+            return
+                {
+                    Code = code
+                    Name = name
+                    FundType = fundType
+                }
+        }
+
+    let private parseObservation root =
+        result {
+            let! navDateText = requiredString root "nav_date"
+            let! navDate = parseDate navDateText
+            let! publishedAtProperty = requiredProperty root "published_at"
+            let! publishedAt = optionalPublishedAt publishedAtProperty
+            let! navProperty = requiredProperty root "nav"
+            let! nav = parseDecimal "nav" navProperty
+            let! accumulatedNavProperty = requiredProperty root "accumulated_nav"
+            let! accumulatedNav = optionalDecimal "accumulated_nav" accumulatedNavProperty
+            let! dailyReturnProperty = requiredProperty root "daily_return"
+            let! dailyReturn = optionalDecimal "daily_return" dailyReturnProperty
+
+            return
+                {
+                    NavDate = navDate
+                    PublishedAt = publishedAt
+                    Nav = nav
+                    AccumulatedNav = accumulatedNav
+                    DailyReturn = dailyReturn
+                }
+        }
+
+    let parseSearchPayload (json: string) : Result<MarketDataSearchPayload, string> =
+        try
+            use document = JsonDocument.Parse(json)
+            let root = document.RootElement
+
+            result {
+                let! source, sourceRevision, collectedAt = validateEnvelope root "search"
+                let! instrumentsProperty = requiredProperty root "instruments"
+                let! instruments = parseArray parseSearchInstrument instrumentsProperty
+
+                return
+                    {
+                        Source = source
+                        SourceRevision = sourceRevision
+                        CollectedAt = collectedAt
+                        Instruments = instruments
+                    }
+            }
+        with
+        | :? JsonException -> Error "payload must be valid JSON"
+
+    let parseNavPayload (json: string) : Result<MarketDataNavPayload, string> =
+        try
+            use document = JsonDocument.Parse(json)
+            let root = document.RootElement
+
+            result {
+                let! source, sourceRevision, collectedAt = validateEnvelope root "nav"
+                let! instrumentProperty = requiredProperty root "instrument"
+                let! code = parseFundCode instrumentProperty
+                let! observationsProperty = requiredProperty root "observations"
+                let! observations = parseArray parseObservation observationsProperty
+
+                if List.isEmpty observations then
+                    return! Error "observations must not be empty"
+
+                return
+                    {
+                        Source = source
+                        SourceRevision = sourceRevision
+                        CollectedAt = collectedAt
+                        Code = code
+                        Observations = observations
+                    }
+            }
+        with
+        | :? JsonException -> Error "payload must be valid JSON"