Add unit tests for Environments, Audit, and Webhooks namespaces (#6)

## Summary
- Add missing unit test coverage for the Environments, Audit, and Webhooks namespaces (raises them from ~0-62% to 91-100%)
- Exclude WebhookBackgroundService/WebhookRetryBackgroundService from coverage (require live DI/DB, disallowed by CLAUDE.md's no-InMemory/WebApplicationFactory rule)

## Test plan
- [x] `dotnet test` full suite passes (646/646)
- [x] Coverage report confirms Environments ~99.5%, Audit 100%, Webhooks ~91%

Reviewed-on: #6

tests/api/MicCheck.Api.Tests.Unit/Audit/AuditLogQueryServiceTests.cs

@@ -0,0 +1,219 @@
+using MicCheck.Api.Audit;
+using MicCheck.Api.Data;
+using MicCheck.Api.Tests.Unit.TestSupport;
+using MicCheck.Api.Users;
+using Moq;
+using NUnit.Framework;
+
+namespace MicCheck.Api.Tests.Unit.Audit;
+
+[TestFixture]
+public class AuditLogQueryServiceTests
+{
+    private Mock<IMicCheckDbContext> _db = null!;
+    private List<AuditLog> _auditLogs = null!;
+    private List<User> _users = null!;
+    private AuditLogQueryService _service = null!;
+
+    private const int OrganizationId = 1;
+    private const int ProjectId = 1;
+    private const int EnvironmentId = 1;
+
+    [SetUp]
+    public void SetUp()
+    {
+        _db = new Mock<IMicCheckDbContext>();
+        _auditLogs = [];
+        _db.SetupDbSet(c => c.AuditLogs, _auditLogs);
+        _users = [];
+        _db.SetupDbSet(c => c.Users, _users);
+
+        _service = new AuditLogQueryService(_db.Object);
+    }
+
+    private AuditLog AddLog(string resourceType = "Feature", string action = "created", int? projectId = ProjectId,
+        int? environmentId = EnvironmentId, int? actorUserId = null, DateTimeOffset? createdAt = null)
+    {
+        var log = new AuditLog
+        {
+            Id = _auditLogs.Count + 1,
+            ResourceType = resourceType,
+            ResourceId = "1",
+            Action = action,
+            OrganizationId = OrganizationId,
+            ProjectId = projectId,
+            EnvironmentId = environmentId,
+            ActorUserId = actorUserId,
+            CreatedAt = createdAt ?? DateTimeOffset.UtcNow
+        };
+        _auditLogs.Add(log);
+        return log;
+    }
+
+    [Test]
+    public async Task WhenListingByOrganization_ThenOnlyLogsForThatOrganizationAreReturned()
+    {
+        AddLog();
+        _auditLogs.Add(new AuditLog { Id = 2, ResourceType = "Feature", ResourceId = "1", Action = "created", OrganizationId = 999, CreatedAt = DateTimeOffset.UtcNow });
+
+        var result = await _service.ListByOrganizationAsync(OrganizationId, new AuditLogFilter());
+
+        Assert.That(result.Total, Is.EqualTo(1));
+        Assert.That(result.Items, Has.Count.EqualTo(1));
+    }
+
+    [Test]
+    public async Task WhenListingByProject_ThenOnlyLogsForThatProjectAreReturned()
+    {
+        AddLog(projectId: ProjectId);
+        AddLog(projectId: 999);
+
+        var result = await _service.ListByProjectAsync(ProjectId, new AuditLogFilter());
+
+        Assert.That(result.Total, Is.EqualTo(1));
+    }
+
+    [Test]
+    public async Task WhenListingByEnvironment_ThenOnlyLogsForThatEnvironmentAreReturned()
+    {
+        AddLog(environmentId: EnvironmentId);
+        AddLog(environmentId: 999);
+
+        var result = await _service.ListByEnvironmentAsync(EnvironmentId, new AuditLogFilter());
+
+        Assert.That(result.Total, Is.EqualTo(1));
+    }
+
+    [Test]
+    public async Task WhenFilteringByFromDate_ThenOnlyLogsOnOrAfterAreReturned()
+    {
+        AddLog(createdAt: DateTimeOffset.UtcNow.AddDays(-10));
+        AddLog(createdAt: DateTimeOffset.UtcNow);
+
+        var result = await _service.ListByOrganizationAsync(OrganizationId, new AuditLogFilter(From: DateTimeOffset.UtcNow.AddDays(-1)));
+
+        Assert.That(result.Total, Is.EqualTo(1));
+    }
+
+    [Test]
+    public async Task WhenFilteringByToDate_ThenOnlyLogsOnOrBeforeAreReturned()
+    {
+        AddLog(createdAt: DateTimeOffset.UtcNow.AddDays(-10));
+        AddLog(createdAt: DateTimeOffset.UtcNow);
+
+        var result = await _service.ListByOrganizationAsync(OrganizationId, new AuditLogFilter(To: DateTimeOffset.UtcNow.AddDays(-1)));
+
+        Assert.That(result.Total, Is.EqualTo(1));
+    }
+
+    [Test]
+    public async Task WhenFilteringByResourceType_ThenOnlyMatchingLogsAreReturned()
+    {
+        AddLog(resourceType: "Feature");
+        AddLog(resourceType: "Segment");
+
+        var result = await _service.ListByOrganizationAsync(OrganizationId, new AuditLogFilter(ResourceType: "Segment"));
+
+        Assert.That(result.Total, Is.EqualTo(1));
+        Assert.That(result.Items[0].ResourceType, Is.EqualTo("Segment"));
+    }
+
+    [Test]
+    public async Task WhenFilteringByAction_ThenOnlyMatchingLogsAreReturned()
+    {
+        AddLog(action: "created");
+        AddLog(action: "deleted");
+
+        var result = await _service.ListByOrganizationAsync(OrganizationId, new AuditLogFilter(Action: "deleted"));
+
+        Assert.That(result.Total, Is.EqualTo(1));
+        Assert.That(result.Items[0].Action, Is.EqualTo("deleted"));
+    }
+
+    [Test]
+    public async Task WhenFilteringByProjectIdOnAnOrganizationQuery_ThenOnlyMatchingLogsAreReturned()
+    {
+        AddLog(projectId: ProjectId);
+        AddLog(projectId: 999);
+
+        var result = await _service.ListByOrganizationAsync(OrganizationId, new AuditLogFilter(ProjectId: ProjectId));
+
+        Assert.That(result.Total, Is.EqualTo(1));
+    }
+
+    [Test]
+    public async Task WhenFilteringByEnvironmentIdOnAnOrganizationQuery_ThenOnlyMatchingLogsAreReturned()
+    {
+        AddLog(environmentId: EnvironmentId);
+        AddLog(environmentId: 999);
+
+        var result = await _service.ListByOrganizationAsync(OrganizationId, new AuditLogFilter(EnvironmentId: EnvironmentId));
+
+        Assert.That(result.Total, Is.EqualTo(1));
+    }
+
+    [Test]
+    public async Task WhenFilteringByActorUserId_ThenOnlyMatchingLogsAreReturned()
+    {
+        AddLog(actorUserId: 1);
+        AddLog(actorUserId: 2);
+
+        var result = await _service.ListByOrganizationAsync(OrganizationId, new AuditLogFilter(ActorUserId: 1));
+
+        Assert.That(result.Total, Is.EqualTo(1));
+    }
+
+    [Test]
+    public async Task WhenPageSizeExceedsMaximum_ThenItIsClampedTo100()
+    {
+        for (var i = 0; i < 150; i++)
+            AddLog();
+
+        var result = await _service.ListByOrganizationAsync(OrganizationId, new AuditLogFilter(PageSize: 1000));
+
+        Assert.That(result.Items, Has.Count.EqualTo(100));
+    }
+
+    [Test]
+    public async Task WhenPageSizeIsBelowMinimum_ThenItIsClampedTo1()
+    {
+        AddLog();
+        AddLog();
+
+        var result = await _service.ListByOrganizationAsync(OrganizationId, new AuditLogFilter(PageSize: 0));
+
+        Assert.That(result.Items, Has.Count.EqualTo(1));
+    }
+
+    [Test]
+    public async Task WhenResultsAreOrderedByCreationDate_ThenNewestAppearsFirst()
+    {
+        AddLog(createdAt: DateTimeOffset.UtcNow.AddDays(-1));
+        var newest = AddLog(createdAt: DateTimeOffset.UtcNow);
+
+        var result = await _service.ListByOrganizationAsync(OrganizationId, new AuditLogFilter());
+
+        Assert.That(result.Items[0].Id, Is.EqualTo(newest.Id));
+    }
+
+    [Test]
+    public async Task WhenALogHasAnActorUser_ThenTheActorUserNameIsPopulated()
+    {
+        _users.Add(new User { Id = 7, Email = "alice@example.com", PasswordHash = "hash", FirstName = "Alice", LastName = "Smith", CreatedAt = DateTimeOffset.UtcNow });
+        AddLog(actorUserId: 7);
+
+        var result = await _service.ListByOrganizationAsync(OrganizationId, new AuditLogFilter());
+
+        Assert.That(result.Items[0].ActorUserName, Is.EqualTo("Alice Smith"));
+    }
+
+    [Test]
+    public async Task WhenALogHasNoActorUser_ThenTheActorUserNameIsNull()
+    {
+        AddLog();
+
+        var result = await _service.ListByOrganizationAsync(OrganizationId, new AuditLogFilter());
+
+        Assert.That(result.Items[0].ActorUserName, Is.Null);
+    }
+}