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/Services/ImageSignatureService.cs

@@ -17,14 +17,10 @@ public sealed class ImageSignatureService
             ?? Environment.GetEnvironmentVariable("DORKNET_IMAGE_SIGNING_KEY_ID")
             ?? "p1");
 
-        // `.rec.net` in the client's `KEY:RSA:p1.rec.net` literal gets byte-rewritten
-        // by patch-client.ps1 to match the server domain (e.g. `.localhost`). The
-        // header suffix we emit has to match that, or the client errors as
-        // "Signature malformed". By default we derive the suffix from the request
-        // Host, which works for the standard same-domain patcher setup. Override
-        // with ImageSigning:KeyIdHostSuffix if your client metadata was patched to
-        // a different value than the server's host (e.g. running the server at
-        // `dorknet.example` while the client metadata still says `localhost`).
+        // 2023 compares Content-Signature's key-id against the embedded
+        // KEY:RSA:p1.rec.net / d1.rec.net literals. If a specific client build
+        // is bytepatched to another suffix, ImageSigning:KeyIdHostSuffix can
+        // override this default.
         configuredKeyIdHostSuffix =
             config["ImageSigning:KeyIdHostSuffix"]
             ?? Environment.GetEnvironmentVariable("DORKNET_IMAGE_SIGNING_KEY_ID_SUFFIX");
@@ -272,19 +268,12 @@ public sealed class ImageSignatureService
 
         var suffix = configuredKeyIdHostSuffix is { Length: > 0 }
             ? configuredKeyIdHostSuffix
-            : ExtractParentDomain(response.HttpContext.Request.Host.Host);
+            : "rec.net";
 
         response.Headers["Content-Signature"] =
             $"key-id=KEY:RSA:{headerKeyId}.{suffix}; data={Convert.ToBase64String(signature)}";
     }
 
-    private static string ExtractParentDomain(string host)
-    {
-        if (string.IsNullOrEmpty(host)) return "rec.net";
-        var dot = host.IndexOf('.');
-        return dot > 0 && dot < host.Length - 1 ? host[(dot + 1)..] : host;
-    }
-
     private static byte[] PlaceholderSignature(byte[] bytes)
     {
         var signature = new byte[128];