feat(item-acquire-history): controller + DTOs

Add ItemAcquireHistoryController (POST /item_acquire_history/info) with its
three DTOs and two integration tests (ordering + empty-viewer). The endpoint
reads ViewerAcquireHistory rows written by InventoryTransaction.CommitAsync,
ordered newest-first, capped at 300. Tests access doc.RootElement.histories
directly (no envelope wrapper in the test path — middleware skips non-UnityPlayer UA).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

SVSim.EmulatedEntrypoint/Controllers/ItemAcquireHistoryController.cs

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+using Microsoft.AspNetCore.Mvc;
+using Microsoft.EntityFrameworkCore;
+using SVSim.Database;
+using SVSim.EmulatedEntrypoint.Models.Dtos.ItemAcquireHistory;
+
+namespace SVSim.EmulatedEntrypoint.Controllers;
+
+[Route("item_acquire_history")]
+public sealed class ItemAcquireHistoryController : SVSimController
+{
+    private const string WireDateFormat = "yyyy-MM-dd HH:mm:ss";
+    private const int PageSize = 300;
+
+    private readonly SVSimDbContext _db;
+
+    public ItemAcquireHistoryController(SVSimDbContext db) => _db = db;
+
+    [HttpPost("info")]
+    public async Task<ActionResult<ItemAcquireHistoryInfoResponse>> Info(
+        [FromBody] ItemAcquireHistoryInfoRequest _,
+        CancellationToken ct)
+    {
+        if (!TryGetViewerId(out var viewerId)) return Unauthorized();
+
+        var rows = await _db.ViewerAcquireHistory
+            .Where(h => h.ViewerId == viewerId)
+            .OrderByDescending(h => h.AcquireTime)
+            .ThenByDescending(h => h.Id)
+            .Take(PageSize)
+            .AsNoTracking()
+            .ToListAsync(ct);
+
+        return new ItemAcquireHistoryInfoResponse
+        {
+            Histories = rows.Select(h => new ItemAcquireHistoryEntryDto
+            {
+                RewardType = h.RewardType.ToString(),
+                RewardDetailId = h.RewardDetailId.ToString(),
+                RewardCount = h.RewardCount.ToString(),
+                AcquireType = h.AcquireType.ToString(),
+                AcquireTime = h.AcquireTime.ToString(WireDateFormat),
+                Message = h.Message,
+            }).ToList(),
+        };
+    }
+}

SVSim.EmulatedEntrypoint/Models/Dtos/ItemAcquireHistory/ItemAcquireHistoryEntryDto.cs

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+using System.Text.Json.Serialization;
+using MessagePack;
+
+namespace SVSim.EmulatedEntrypoint.Models.Dtos.ItemAcquireHistory;
+
+/// <summary>
+/// One row in the <c>/item_acquire_history/info</c> response. All numeric fields ship as
+/// decimal strings to match the prod capture.
+/// </summary>
+[MessagePackObject]
+public sealed class ItemAcquireHistoryEntryDto
+{
+    [JsonPropertyName("reward_type")]
+    [Key("reward_type")]
+    public string RewardType { get; set; } = "0";
+
+    [JsonPropertyName("reward_detail_id")]
+    [Key("reward_detail_id")]
+    public string RewardDetailId { get; set; } = "0";
+
+    [JsonPropertyName("reward_count")]
+    [Key("reward_count")]
+    public string RewardCount { get; set; } = "0";
+
+    [JsonPropertyName("acquire_type")]
+    [Key("acquire_type")]
+    public string AcquireType { get; set; } = "0";
+
+    [JsonPropertyName("acquire_time")]
+    [Key("acquire_time")]
+    public string AcquireTime { get; set; } = string.Empty;
+
+    [JsonPropertyName("message")]
+    [Key("message")]
+    public string Message { get; set; } = string.Empty;
+}

SVSim.EmulatedEntrypoint/Models/Dtos/ItemAcquireHistory/ItemAcquireHistoryInfoRequest.cs

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+using MessagePack;
+
+namespace SVSim.EmulatedEntrypoint.Models.Dtos.ItemAcquireHistory;
+
+/// <summary>
+/// Empty request body. The endpoint takes no parameters; this DTO exists so model binding
+/// resolves the envelope correctly.
+/// </summary>
+[MessagePackObject(true)]
+public sealed class ItemAcquireHistoryInfoRequest
+{
+}

SVSim.EmulatedEntrypoint/Models/Dtos/ItemAcquireHistory/ItemAcquireHistoryInfoResponse.cs

@@ -0,0 +1,12 @@
+using System.Text.Json.Serialization;
+using MessagePack;
+
+namespace SVSim.EmulatedEntrypoint.Models.Dtos.ItemAcquireHistory;
+
+[MessagePackObject]
+public sealed class ItemAcquireHistoryInfoResponse
+{
+    [JsonPropertyName("histories")]
+    [Key("histories")]
+    public List<ItemAcquireHistoryEntryDto> Histories { get; set; } = new();
+}

SVSim.UnitTests/Controllers/ItemAcquireHistoryControllerTests.cs

@@ -0,0 +1,85 @@
+using System.Net;
+using System.Text;
+using System.Text.Json;
+using Microsoft.Extensions.DependencyInjection;
+using SVSim.Database;
+using SVSim.Database.Models;
+using SVSim.Database.Services.Inventory;
+using SVSim.UnitTests.Infrastructure;
+
+namespace SVSim.UnitTests.Controllers;
+
+public class ItemAcquireHistoryControllerTests
+{
+    private static StringContent JsonBody(string json) => new(json, Encoding.UTF8, "application/json");
+
+    [Test]
+    public async Task Info_returns_history_in_newest_first_order_for_the_authenticated_viewer()
+    {
+        using var factory = new SVSimTestFactory();
+        long viewerA = await factory.SeedViewerAsync(steamId: 76_561_198_000_000_001UL);
+        long viewerB = await factory.SeedViewerAsync(steamId: 76_561_198_000_000_002UL);
+
+        using var seedScope = factory.Services.CreateScope();
+        var ctx = seedScope.ServiceProvider.GetRequiredService<SVSimDbContext>();
+        var baseTime = new DateTime(2026, 6, 9, 12, 0, 0, DateTimeKind.Utc);
+        for (int i = 0; i < 5; i++)
+        {
+            ctx.ViewerAcquireHistory.Add(new ViewerAcquireHistoryEntry
+            {
+                ViewerId = viewerA,
+                RewardType = 9,
+                RewardDetailId = 0,
+                RewardCount = i + 1,
+                AcquireType = (int)GrantSource.DailyBonus,
+                Message = "Daily Bonus",
+                AcquireTime = baseTime.AddMinutes(i),
+            });
+        }
+        ctx.ViewerAcquireHistory.Add(new ViewerAcquireHistoryEntry
+        {
+            ViewerId = viewerB,
+            RewardType = 9, RewardDetailId = 0, RewardCount = 99,
+            AcquireType = (int)GrantSource.PackOpen, Message = "x", AcquireTime = baseTime,
+        });
+        await ctx.SaveChangesAsync();
+
+        using var client = factory.CreateAuthenticatedClient(viewerA);
+        var response = await client.PostAsync("/item_acquire_history/info",
+            JsonBody("""{"viewer_id":"0","steam_id":0,"steam_session_ticket":""}"""));
+        var raw = await response.Content.ReadAsStringAsync();
+        Assert.That(response.StatusCode, Is.EqualTo(HttpStatusCode.OK), raw);
+
+        // Tests bypass the translation middleware (no UnityPlayer UA), so the response is
+        // the raw controller JSON — no {data_headers, data} envelope.
+        using var doc = JsonDocument.Parse(raw);
+        var histories = doc.RootElement.GetProperty("histories");
+
+        Assert.That(histories.GetArrayLength(), Is.EqualTo(5));
+        // Newest first: i=4 was AcquireTime+4min → reward_count = "5"
+        Assert.That(histories[0].GetProperty("reward_count").GetString(), Is.EqualTo("5"));
+        Assert.That(histories[4].GetProperty("reward_count").GetString(), Is.EqualTo("1"));
+        for (int i = 0; i < 5; i++)
+        {
+            Assert.That(histories[i].GetProperty("acquire_type").GetString(),
+                Is.EqualTo("1"), $"histories[{i}].acquire_type should be DailyBonus=1");
+        }
+    }
+
+    [Test]
+    public async Task Info_returns_empty_array_for_viewer_with_no_history()
+    {
+        using var factory = new SVSimTestFactory();
+        long viewerId = await factory.SeedViewerAsync();
+
+        using var client = factory.CreateAuthenticatedClient(viewerId);
+        var response = await client.PostAsync("/item_acquire_history/info",
+            JsonBody("""{"viewer_id":"0","steam_id":0,"steam_session_ticket":""}"""));
+        var raw = await response.Content.ReadAsStringAsync();
+        Assert.That(response.StatusCode, Is.EqualTo(HttpStatusCode.OK), raw);
+
+        using var doc = JsonDocument.Parse(raw);
+        var histories = doc.RootElement.GetProperty("histories");
+        Assert.That(histories.GetArrayLength(), Is.EqualTo(0));
+    }
+}