修复500

TimeOnly ↔ TimeSpan

src/Jiaowu.Api/Infrastructure/Persistence/AppDbContext.cs

@@ -101,6 +101,12 @@ public sealed class AppDbContext(DbContextOptions<AppDbContext> options)
         configurationBuilder.Properties<DateOnly>()
             .HaveConversion<DateOnlyDateTimeConverter>()
             .HaveColumnType("date");
+
+        // Connector/NET returns MySQL TIME values as TimeSpan. Convert at the
+        // provider boundary so schedule time slots can still use TimeOnly.
+        configurationBuilder.Properties<TimeOnly>()
+            .HaveConversion<TimeOnlyTimeSpanConverter>()
+            .HaveColumnType("time");
     }
 
     protected override void OnModelCreating(ModelBuilder builder)
@@ -931,3 +937,8 @@ public sealed class DateOnlyDateTimeConverter()
     : ValueConverter<DateOnly, DateTime>(
         date => date.ToDateTime(TimeOnly.MinValue),
         value => DateOnly.FromDateTime(value));
+
+public sealed class TimeOnlyTimeSpanConverter()
+    : ValueConverter<TimeOnly, TimeSpan>(
+        time => time.ToTimeSpan(),
+        value => TimeOnly.FromTimeSpan(value));