test(harness): stabilize backend+frontend QA test suite (12/12+63/63 unit+integration, 45/45 frontend)

Stabilize test harness across full stack:

Backend integration tests:
- Fix Auth/Club/Migration/RLS/Member/Tenant/RLS Isolation/Shift/Task test suites
- Add AssemblyInfo.cs for test configuration
- Enhance CustomWebApplicationFactory + TestAuthHandler for stable test environment
- Expand RlsIsolationTests with comprehensive multi-tenant RLS verification

Frontend test harness:
- Align vitest.config.ts with backend API changes
- Add bunfig.toml for bun test environment stability
- Enhance api.test.ts with proper test setup integration
- Expand test/setup.ts with fixture initialization

All tests now passing: backend 12/12 unit + 63/63 integration, frontend 45/45

backend/WorkClub.Tests.Integration/Shifts/ShiftCrudTests.cs

@@ -86,7 +86,6 @@ public class ShiftCrudTests : IntegrationTestBase
     [Fact]
     public async Task ListShifts_WithDateFilter_ReturnsFilteredShifts()
     {
-        // Arrange
         var clubId = Guid.NewGuid();
         var createdBy = Guid.NewGuid();
         var now = DateTimeOffset.UtcNow;
@@ -95,7 +94,6 @@ public class ShiftCrudTests : IntegrationTestBase
         {
             var context = scope.ServiceProvider.GetRequiredService<AppDbContext>();
 
-            // Shift in date range
             context.Shifts.Add(new Shift
             {
                 Id = Guid.NewGuid(),
@@ -110,7 +108,6 @@ public class ShiftCrudTests : IntegrationTestBase
                 UpdatedAt = now
             });
 
-            // Shift outside date range
             context.Shifts.Add(new Shift
             {
                 Id = Guid.NewGuid(),
@@ -131,13 +128,11 @@ public class ShiftCrudTests : IntegrationTestBase
         SetTenant("tenant1");
         AuthenticateAs("member@test.com", new Dictionary<string, string> { ["tenant1"] = "Member" });
 
-        var from = now.AddDays(1).ToString("o");
-        var to = now.AddDays(5).ToString("o");
+        var from = Uri.EscapeDataString(now.AddDays(1).ToString("o"));
+        var to = Uri.EscapeDataString(now.AddDays(5).ToString("o"));
 
-        // Act
         var response = await Client.GetAsync($"/api/shifts?from={from}&to={to}");
 
-        // Assert
         Assert.Equal(HttpStatusCode.OK, response.StatusCode);
 
         var result = await response.Content.ReadFromJsonAsync<ShiftListResponse>();