House rules: numbers through one formatter, no made-up server errors, and the rules fail the build

- Every number shown on a page goes through NumbersExtensions: counts,
  percentages, the nerd readouts and the values written into a style.
- A failure the client builds itself (offline, timeout, retries run out, an
  answer it can't read) is a 400 that names its kind; only a server's own 5XX
  passes through.
- Login, sign-up, recovery and password confirmations leave autocomplete to
  the browser, so it can offer the saved login.
- The Daisy components start with empty lists and attributes, and a
  decorative image still renders alt="".
- Arasaka.HouseRules.Analyzers checks all of this in every build, together
  with PrivaPub.ClientModels.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01W4YtEJrgxG12Pc39Fai8Bd

Services/StreamingService.cs

@@ -183,7 +183,7 @@ namespace decePubClient.Services
 			while (socket.State == WebSocketState.Open)
 			{
 				var text = new StringBuilder();
-				WebSocketReceiveResult received;
+				var received = default(WebSocketReceiveResult);
 				do
 				{
 					received = await socket.ReceiveAsync(buffer, cancellationToken);
@@ -229,7 +229,7 @@ namespace decePubClient.Services
 
 		/// <summary>Closes the socket; the page polls from then on. The announcements stay asked for: the next Follow opens
 		/// the socket for them too.</summary>
-		public async Task Stop()
+		public async Task Stop(CancellationToken cancellationToken = default)
 		{
 			current = null;
 			if (running is not null)