feat(api,web): 模拟认购订单创建/读取，幂等与预留现金（3d-1）

- API: POST/GET /api/funds/{fundId}/orders，advisory lock + 行级锁事务预留现金，
  幂等键重放/冲突/校验/目录缺失错误码齐全，基金响应新增 reservedCash
- Persistence: subscription_orders 与幂等表 + 保留现金列迁移
- Web: 认购表单与待确认订单列表（已提交·待确认），失败重试复用幂等键，
  token 轮换隔离延迟响应
- 测试: API 41（含并发不足/回滚/真实宿主重启回归）、Web 17、Domain 19；
  浏览器 QA 58 项全过

3 files changed, 402 insertions, 0 deletions

diff --git a/tests/FundLab.Api.Tests/FundLab.Api.Tests.fsproj b/tests/FundLab.Api.Tests/FundLab.Api.Tests.fsproj
index 63f0750..21778a3 100644
--- a/tests/FundLab.Api.Tests/FundLab.Api.Tests.fsproj
+++ b/tests/FundLab.Api.Tests/FundLab.Api.Tests.fsproj
@@ -23,6 +23,7 @@
     <Compile Include="ApiTests.fs" />
     <Compile Include="ProcessCollectorTests.fs" />
     <Compile Include="PersistenceTests.fs" />
+    <Compile Include="OrderTests.fs" />
     <Compile Include="Program.fs" />
   </ItemGroup>
 </Project>
diff --git a/tests/FundLab.Api.Tests/OrderTests.fs b/tests/FundLab.Api.Tests/OrderTests.fs
new file mode 100644
index 0000000..5e6771c
--- /dev/null
+++ b/tests/FundLab.Api.Tests/OrderTests.fs
@@ -0,0 +1,400 @@
+namespace FundLab.Api.Tests
+
+open System
+open System.Collections.Concurrent
+open System.Net.Http
+open System.Text.Json
+open System.Threading.Tasks
+open FundLab.Api
+open Xunit
+
+[<Collection("postgres")>]
+type OrderTests(fixture: PostgresFixture) =
+    let repository () =
+        let value = FundRepository(fixture.ConnectionString)
+        value.EnsureSchema()
+        value
+
+    let seedInstrument () =
+        let code = Random.Shared.Next(0, 1000000).ToString("D6")
+        let payload =
+            {
+                Source = "akshare"
+                SourceRevision = "akshare-test/eastmoney"
+                CollectedAt = DateTimeOffset(2026, 9, 21, 10, 0, 0, TimeSpan.Zero)
+                Instruments = [ { Code = code; Name = "订单测试基金"; FundType = None } ]
+            }
+
+        repository().UpsertInstruments(payload, "order-test-hash")
+        code
+
+    let createFund (initialCash: decimal) =
+        let command =
+            {
+                Name = "订单测试 FOF"
+                InitialCash = initialCash
+                InitialUnitNav = 1.00000000m
+                IsSynthetic = true
+            }
+
+        let key = fixture.Key(sprintf "order-fund-%s" (Guid.NewGuid().ToString("N")))
+
+        match repository().CreateFund(key, command) with
+        | FundWriteResult.Created fund -> fund.Id
+        | other -> failwithf "unexpected fund creation result: %A" other
+
+    let app () = App.createApplication (repository ())
+
+    let orderBody fundCode amount fee =
+        sprintf "{\"fundCode\":\"%s\",\"amount\":\"%s\",\"feeAmount\":\"%s\"}" fundCode amount fee
+
+    let postOrder (api) fundId idempotencyKey body =
+        PersistenceTestHelpers.invoke
+            api
+            "POST"
+            (sprintf "/api/funds/%O/orders" fundId)
+            [
+                "Authorization", "Bearer test-token"
+                "Idempotency-Key", idempotencyKey
+            ]
+            body
+
+    let getOrderList (api) fundId =
+        PersistenceTestHelpers.invoke
+            api
+            "GET"
+            (sprintf "/api/funds/%O/orders" fundId)
+            [ "Authorization", "Bearer test-token" ]
+            ""
+
+    let getFund (api) fundId =
+        PersistenceTestHelpers.invoke
+            api
+            "GET"
+            (sprintf "/api/funds/%O" fundId)
+            [ "Authorization", "Bearer test-token" ]
+            ""
+
+    let jsonProperty (body: string) (name: string) =
+        use document = JsonDocument.Parse(body)
+        document.RootElement.GetProperty(name).GetString()
+
+    let orderCount (body: string) =
+        use document = JsonDocument.Parse(body)
+        document.RootElement.GetArrayLength()
+
+    [<Fact>]
+    member _.``subscription order reserves cash and stays visible as pending``() =
+        let code = seedInstrument ()
+        let fundId = createFund 1000.00m
+        let api = app ()
+        let key = fixture.Key("order-happy-path")
+
+        let status, body =
+            postOrder api fundId key (orderBody code "100.00" "1.50")
+
+        Assert.Equal(201, status)
+        Assert.Contains(sprintf "\"fundCode\":\"%s\"" code, body)
+        Assert.Contains("\"amount\":\"100.00\"", body)
+        Assert.Contains("\"feeAmount\":\"1.50\"", body)
+        Assert.Contains("\"reservedTotal\":\"101.50\"", body)
+        Assert.Contains("\"status\":\"submitted\"", body)
+        Assert.Contains(sprintf "\"fundId\":\"%O\"" fundId, body)
+
+        let orderId = PersistenceTestHelpers.responseId body
+
+        let fundStatus, fundBody = getFund api fundId
+        Assert.Equal(200, fundStatus)
+        Assert.Contains("\"availableCash\":\"898.50\"", fundBody)
+        Assert.Contains("\"reservedCash\":\"101.50\"", fundBody)
+
+        let listStatus, listBody = getOrderList api fundId
+        Assert.Equal(200, listStatus)
+        Assert.Equal(1, orderCount listBody)
+        Assert.Contains(sprintf "\"id\":\"%O\"" orderId, listBody)
+
+    [<Fact>]
+    member _.``subscription order replays the same order for an identical idempotency key``() =
+        let code = seedInstrument ()
+        let fundId = createFund 500.00m
+        let api = app ()
+        let key = fixture.Key("order-replay")
+        let body = orderBody code "50.00" "2.50"
+
+        let createStatus, createResponse = postOrder api fundId key body
+        Assert.Equal(201, createStatus)
+        let orderId = PersistenceTestHelpers.responseId createResponse
+
+        let replayStatus, replayResponse = postOrder api fundId key body
+        Assert.Equal(200, replayStatus)
+        Assert.Equal(orderId, PersistenceTestHelpers.responseId replayResponse)
+
+        let _, fundBody = getFund api fundId
+        Assert.Contains("\"availableCash\":\"447.50\"", fundBody)
+        Assert.Contains("\"reservedCash\":\"52.50\"", fundBody)
+
+        let _, listBody = getOrderList api fundId
+        Assert.Equal(1, orderCount listBody)
+
+    [<Fact>]
+    member _.``subscription order rejects conflicting reuse of an idempotency key``() =
+        let code = seedInstrument ()
+        let fundId = createFund 300.00m
+        let api = app ()
+        let key = fixture.Key("order-conflict")
+
+        let _, _ = postOrder api fundId key (orderBody code "30.00" "3.00")
+
+        let conflictStatus, conflictBody =
+            postOrder api fundId key (orderBody code "31.00" "3.00")
+
+        Assert.Equal(409, conflictStatus)
+        Assert.Contains("IDEMPOTENCY_CONFLICT", conflictBody)
+
+        let _, fundBody = getFund api fundId
+        Assert.Contains("\"availableCash\":\"267.00\"", fundBody)
+        Assert.Contains("\"reservedCash\":\"33.00\"", fundBody)
+
+    [<Fact>]
+    member _.``subscription order validates amount fee and catalog input``() =
+        let code = seedInstrument ()
+        let fundId = createFund 1000.00m
+        let api = app ()
+        let key = fixture.Key("order-validation")
+
+        let invalidBodies =
+            [
+                orderBody code "0.00" "1.00"
+                orderBody code "-5.00" "1.00"
+                orderBody code "10.005" "1.00"
+                orderBody code "10.00" "0.00"
+                orderBody code "10.00" "1.005"
+                "{\"amount\":\"10.00\",\"feeAmount\":\"1.00\"}"
+                "{\"fundCode\":123,\"amount\":\"10.00\",\"feeAmount\":\"1.00\"}"
+                "{\"fundCode\":\"" + code + "\",\"amount\":\"abc\",\"feeAmount\":\"1.00\"}"
+                "[]"
+                ""
+            ]
+
+        for invalidBody in invalidBodies do
+            let status, responseBody = postOrder api fundId key invalidBody
+            Assert.Equal(400, status)
+            Assert.Contains("INVALID_ORDER_REQUEST", responseBody)
+
+        let _, fundBody = getFund api fundId
+        Assert.Contains("\"availableCash\":\"1000.00\"", fundBody)
+        Assert.Contains("\"reservedCash\":\"0.00\"", fundBody)
+
+        let _, listBody = getOrderList api fundId
+        Assert.Equal(0, orderCount listBody)
+
+        let boundaryStatus, boundaryBody =
+            postOrder api fundId key (orderBody code "0.01" "0.01")
+
+        Assert.Equal(201, boundaryStatus)
+        Assert.Contains("\"reservedTotal\":\"0.02\"", boundaryBody)
+
+        let _, fundAfterBoundary = getFund api fundId
+        Assert.Contains("\"availableCash\":\"999.98\"", fundAfterBoundary)
+        Assert.Contains("\"reservedCash\":\"0.02\"", fundAfterBoundary)
+
+    [<Fact>]
+    member _.``subscription order requires authentication and an idempotency key``() =
+        let fundId = createFund 100.00m
+        let api = app ()
+        let body = orderBody "000001" "10.00" "1.00"
+
+        let unauthorizedStatus, _ =
+            PersistenceTestHelpers.invoke
+                api
+                "POST"
+                (sprintf "/api/funds/%O/orders" fundId)
+                [ "Idempotency-Key", fixture.Key("order-unauthorized") ]
+                body
+
+        Assert.Equal(401, unauthorizedStatus)
+
+        let missingKeyStatus, missingKeyBody =
+            PersistenceTestHelpers.invoke
+                api
+                "POST"
+                (sprintf "/api/funds/%O/orders" fundId)
+                [ "Authorization", "Bearer test-token" ]
+                body
+
+        Assert.Equal(400, missingKeyStatus)
+        Assert.Contains("INVALID_ORDER_REQUEST", missingKeyBody)
+
+    [<Fact>]
+    member _.``subscription order rejects unknown funds and unknown fund codes without cash movement``() =
+        let code = seedInstrument ()
+        let fundId = createFund 800.00m
+        let api = app ()
+
+        let invalidIdStatus, invalidIdBody =
+            PersistenceTestHelpers.invoke
+                api
+                "POST"
+                "/api/funds/not-a-guid/orders"
+                [
+                    "Authorization", "Bearer test-token"
+                    "Idempotency-Key", fixture.Key("order-bad-id")
+                ]
+                (orderBody code "10.00" "1.00")
+
+        Assert.Equal(400, invalidIdStatus)
+        Assert.Contains("INVALID_FUND_ID", invalidIdBody)
+
+        let unknownFundStatus, unknownFundBody =
+            postOrder api (Guid.NewGuid()) (fixture.Key("order-unknown-fund")) (orderBody code "10.00" "1.00")
+
+        Assert.Equal(404, unknownFundStatus)
+        Assert.Contains("FUND_NOT_FOUND", unknownFundBody)
+
+        let unknownCodeStatus, unknownCodeBody =
+            postOrder api fundId (fixture.Key("order-unknown-code")) (orderBody "999999" "10.00" "1.00")
+
+        Assert.Equal(404, unknownCodeStatus)
+        Assert.Contains("INSTRUMENT_NOT_FOUND", unknownCodeBody)
+
+        let _, fundBody = getFund api fundId
+        Assert.Contains("\"availableCash\":\"800.00\"", fundBody)
+        Assert.Contains("\"reservedCash\":\"0.00\"", fundBody)
+
+        let _, listBody = getOrderList api fundId
+        Assert.Equal(0, orderCount listBody)
+
+        let missingListStatus, _ = getOrderList api (Guid.NewGuid())
+        Assert.Equal(404, missingListStatus)
+
+    [<Fact>]
+    member _.``subscription order refuses insufficient available cash atomically``() =
+        let code = seedInstrument ()
+        let fundId = createFund 10.00m
+        let api = app ()
+
+        let status, body = postOrder api fundId (fixture.Key("order-insufficient")) (orderBody code "6.00" "5.00")
+
+        Assert.Equal(409, status)
+        Assert.Contains("INSUFFICIENT_FUNDS", body)
+
+        let _, fundBody = getFund api fundId
+        Assert.Contains("\"availableCash\":\"10.00\"", fundBody)
+        Assert.Contains("\"reservedCash\":\"0.00\"", fundBody)
+
+        let _, listBody = getOrderList api fundId
+        Assert.Equal(0, orderCount listBody)
+
+    [<Fact>]
+    member _.``concurrent subscription orders reserve exactly the affordable amount``() =
+        let code = seedInstrument ()
+        let fundId = createFund 10.00m
+        let api = app ()
+        let body = orderBody code "3.50" "0.50"
+        let statuses = ConcurrentBag<int>()
+
+        Parallel.For(
+            0,
+            8,
+            fun index ->
+                let key = fixture.Key(sprintf "order-concurrent-%s-%d" (Guid.NewGuid().ToString("N")) index)
+                let status, _ = postOrder api fundId key body
+                statuses.Add(status)
+        )
+        |> ignore
+
+        Assert.Equal(2, (statuses |> Seq.filter (fun status -> status = 201) |> Seq.length))
+        Assert.Equal(6, (statuses |> Seq.filter (fun status -> status = 409) |> Seq.length))
+
+        let _, fundBody = getFund api fundId
+        Assert.Contains("\"availableCash\":\"2.00\"", fundBody)
+        Assert.Contains("\"reservedCash\":\"8.00\"", fundBody)
+
+        let _, listBody = getOrderList api fundId
+        Assert.Equal(2, orderCount listBody)
+
+    [<Fact>]
+    member _.``real Kestrel API preserves subscription orders and idempotency across process restart``() =
+        let code = seedInstrument ()
+        let key = fixture.Key("order-restart")
+
+        use firstProcess = new ApiProcess(fixture.ConnectionString)
+        PersistenceTestHelpers.waitForApi firstProcess
+
+        use client = new HttpClient()
+        client.BaseAddress <- Uri(firstProcess.BaseAddress)
+
+        let fundBody =
+            "{\"name\":\"订单重启 FOF\",\"initialCash\":\"100.00\",\"initialUnitNav\":\"1.00000000\",\"isSynthetic\":true}"
+
+        let fundStatus, fundResponse =
+            PersistenceTestHelpers.send
+                client
+                "POST"
+                "/api/funds"
+                (Some "test-token")
+                (Some(fixture.Key("order-restart-fund")))
+                fundBody
+
+        Assert.Equal(201, fundStatus)
+        let fundId = PersistenceTestHelpers.responseId fundResponse
+
+        let createStatus, createResponse =
+            PersistenceTestHelpers.send
+                client
+                "POST"
+                (sprintf "/api/funds/%O/orders" fundId)
+                (Some "test-token")
+                (Some key)
+                (orderBody code "60.00" "4.00")
+
+        Assert.Equal(201, createStatus)
+        Assert.Contains("\"reservedTotal\":\"64.00\"", createResponse)
+        Assert.Contains("\"status\":\"submitted\"", createResponse)
+        let orderId = PersistenceTestHelpers.responseId createResponse
+
+        firstProcess.Stop() |> ignore
+
+        use restartedProcess = new ApiProcess(fixture.ConnectionString)
+        PersistenceTestHelpers.waitForApi restartedProcess
+
+        use restartedClient = new HttpClient()
+        restartedClient.BaseAddress <- Uri(restartedProcess.BaseAddress)
+
+        let restartedFundStatus, restartedFundBody =
+            PersistenceTestHelpers.send
+                restartedClient
+                "GET"
+                (sprintf "/api/funds/%O" fundId)
+                (Some "test-token")
+                None
+                ""
+
+        Assert.Equal(200, restartedFundStatus)
+        Assert.Contains("\"availableCash\":\"36.00\"", restartedFundBody)
+        Assert.Contains("\"reservedCash\":\"64.00\"", restartedFundBody)
+
+        let restartedOrderListStatus, restartedOrderListBody =
+            PersistenceTestHelpers.send
+                restartedClient
+                "GET"
+                (sprintf "/api/funds/%O/orders" fundId)
+                (Some "test-token")
+                None
+                ""
+
+        Assert.Equal(200, restartedOrderListStatus)
+        Assert.Equal(1, orderCount restartedOrderListBody)
+        Assert.Contains(sprintf "\"id\":\"%O\"" orderId, restartedOrderListBody)
+
+        let replayStatus, replayResponse =
+            PersistenceTestHelpers.send
+                restartedClient
+                "POST"
+                (sprintf "/api/funds/%O/orders" fundId)
+                (Some "test-token")
+                (Some key)
+                (orderBody code "60.00" "4.00")
+
+        Assert.Equal(200, replayStatus)
+        Assert.Equal(orderId, PersistenceTestHelpers.responseId replayResponse)
diff --git a/tests/FundLab.Web.Tests/BoundaryTests.fs b/tests/FundLab.Web.Tests/BoundaryTests.fs
index ed970bd..1d021a1 100644
--- a/tests/FundLab.Web.Tests/BoundaryTests.fs
+++ b/tests/FundLab.Web.Tests/BoundaryTests.fs
@@ -161,6 +161,7 @@ module FundBoundaryTests =
             initialUnitNav = "1.00000000"
             isSynthetic = false
             availableCash = "12345.67"
+            reservedCash = "0.00"
             status = "active"
         }