Update wire protocol to version 6 and enhance timetable functionality

- Bumped the wire protocol version to 6, reflecting changes in the communication structure.
- Expanded the timetable API with new endpoints for fetching and managing lesson schedules, including `GET /api/schools/{id}/timetable` and `POST /api/schools/{id}/timetable/pin`.
- Updated the protocol documentation to include detailed descriptions of the new timetable features and message structures.
- Enhanced the client-side implementation to support the new timetable functionalities, including lesson pinning and unpinning.
- Revised server-side logic to handle timetable operations and ensure proper integration with existing school management features.
- Added tests to validate the new timetable functionalities and ensure robustness in handling lesson data.

src/HSchool.Simulation/HSchool.Simulation.csproj

@@ -12,6 +12,7 @@
     <ItemGroup>
       <ProjectReference Include="..\HSchool.Content\HSchool.Content.csproj" />
       <ProjectReference Include="..\HSchool.People\HSchool.People.csproj" />
+      <ProjectReference Include="..\HSchool.Schedule\HSchool.Schedule.csproj" />
     </ItemGroup>
 
 </Project>