Update wire protocol to version 7 and enhance presence management features

- Bumped the wire protocol version to 7, reflecting significant changes in the communication structure.
- Introduced a new presence message type for real-time occupancy updates, including node activity and individual presence states.
- Updated the API to include a directory endpoint for fetching short id→name mappings, improving client-side name resolution.
- Revised the map snapshot structure to be static, with people and current lessons now handled through the presence stream.
- Enhanced client-side handling of presence updates, including UI adjustments to display live occupancy and activity.
- Updated documentation to reflect the new protocol features and changes in presence management.
- Added tests to validate the new presence functionalities and ensure robust handling of real-time data.

src/HSchool.Server/Api/SchoolEndpoints.cs

@@ -134,6 +134,29 @@ internal static class SchoolEndpoints
         })
         .WithName("GetSchoolPeople");
 
+        schools.MapGet("/{id:int}/directory", (int id, string? lang, GameLoopService loop) =>
+        {
+            var published = loop.FindPeople(id);
+            if (published is null)
+            {
+                return Problem(StatusCodes.Status404NotFound, "unknown-school", "That school does not exist.");
+            }
+
+            _ = ParseLocale(lang);
+            var roster = published.Roster;
+            if (roster is null)
+            {
+                return Results.Ok(new DirectoryResponse([]));
+            }
+
+            var people = roster.People
+                .OrderBy(person => person.Id, StringComparer.Ordinal)
+                .Select(person => new DirectoryPersonResponse(person.Id, person.Name.Full))
+                .ToArray();
+            return Results.Ok(new DirectoryResponse(people));
+        })
+        .WithName("GetSchoolDirectory");
+
         schools.MapGet("/{id:int}/people/{personId}", async (
             int id,
             string personId,