feat: Enhance UgcPurchasablesController to handle bulk requests with object arrays

- Updated Bulk method to parse incoming JSON object arrays for UGC item IDs.
- Introduced ReadBulkIdsAsync to handle both object arrays and flat GUID lists.
- Added synthetic placeholder responses for missing UGC items to prevent client errors.

feat: Implement MatchmakeRoom and MatchmakeSubRoom endpoints in GoToController

- Added MatchmakeRoom and MatchmakeSubRoom methods to facilitate joining public and sub-rooms by numeric ID.
- Enhanced ApplySubRoomMutation to ensure proper state transitions for sub-rooms.
- Improved logging for matchmaking actions.

fix: Refactor PlayerSettingsController to handle database save exceptions

- Introduced SaveSettingsChangesAsync to manage DbUpdateException for busy SQLite scenarios.
- Updated methods to call SaveSettingsChangesAsync instead of direct SaveChangesAsync.

chore: Update URL coverage documentation for new matchmaking endpoints

- Documented new MatchmakeRoom and MatchmakeSubRoom endpoints in url-coverage.md.

chore: Add default room data file for room loading

- Included default_room.room to serve as a fallback for missing room data.

fix: Improve SQLite concurrency handling in DatabaseBootstrap

- Configured SQLite to use WAL mode and set a busy timeout for better concurrency.

chore: Create SqliteErrors utility for handling SQLite exceptions

- Added SqliteErrors class to encapsulate logic for detecting busy SQLite exceptions.

refactor: Update RoomDataBlobService to serve default room data

- Modified GetDefaultBlob to load and serve a default room blob with proper role data.

DorkNet.Server/Data/SqliteErrors.cs

@@ -0,0 +1,19 @@
+using Microsoft.Data.Sqlite;
+using Microsoft.EntityFrameworkCore;
+
+namespace DorkNet.Server.Data;
+
+internal static class SqliteErrors
+{
+    public static bool IsBusy(DbUpdateException ex)
+    {
+        for (Exception? current = ex; current is not null; current = current.InnerException)
+        {
+            if (current is SqliteException sqlite &&
+                (sqlite.SqliteErrorCode == 5 || sqlite.SqliteErrorCode == 6))
+                return true;
+        }
+
+        return false;
+    }
+}