feat(console): add --list-sources diagnostic flag

Enumerates every raw NDI source string visible to the local NDI finder for ~5 seconds and prints unique ones, then exits. Bypasses NdiSourceParser so it surfaces sources that the parser would otherwise reject — useful for confirming the on-the-wire format Teams (or any other producer) is actually emitting on a given setup.

Used directly to diagnose the Teams 'MS Teams' vs. 'Teams' brand-prefix mismatch fixed in the previous commit; left in as a permanent debug tool for future setup issues.

src/TeamsISO.Console/Program.cs

@@ -1,4 +1,5 @@
 using System.Reactive.Linq;
+using System.Runtime.Versioning;
 using Microsoft.Extensions.Logging;
 using TeamsISO.Engine.Controller;
 using TeamsISO.Engine.Domain;
@@ -22,12 +23,16 @@ using SysConsole = System.Console;
 /// Usage:
 ///   teamsiso-console                   # discover only — print participants as they appear/leave
 ///   teamsiso-console --enable-all      # auto-enable an ISO for every discovered participant
+///   teamsiso-console --list-sources    # diagnostic: print every raw NDI source string visible
+///                                        on the network for ~5s, then exit. Useful for debugging
+///                                        why expected Teams sources aren't being classified.
 /// </summary>
 public static class Program
 {
     public static async Task<int> Main(string[] args)
     {
         var enableAll = args.Contains("--enable-all", StringComparer.OrdinalIgnoreCase);
+        var listSources = args.Contains("--list-sources", StringComparer.OrdinalIgnoreCase);
         using var loggerFactory = EngineLogging.CreateConsole(LogLevel.Information);
         var logger = loggerFactory.CreateLogger("TeamsISO.Console");
 
@@ -48,6 +53,11 @@ public static class Program
             return 2;
         }
 
+        if (listSources)
+        {
+            return await RunListSourcesAsync(interop, logger);
+        }
+
         var configPath = Path.Combine(
             Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData),
             "TeamsISO", "config.json");
@@ -125,4 +135,35 @@ public static class Program
         logger.LogInformation("Engine stopped.");
         return 0;
     }
+
+    /// <summary>
+    /// Diagnostic mode: enumerates every raw NDI source string visible to the local
+    /// NDI finder for ~5 seconds, prints each unique one, then exits. Bypasses the
+    /// <see cref="Discovery.NdiSourceParser"/> entirely, so it surfaces sources that
+    /// the parser would otherwise reject — useful for confirming the on-the-wire
+    /// format Teams (or any other producer) is actually emitting.
+    /// </summary>
+    [SupportedOSPlatform("windows")]
+    private static async Task<int> RunListSourcesAsync(NdiInteropPInvoke interop, ILogger logger)
+    {
+        const int pollMs = 500;
+        const int totalMs = 5000;
+        logger.LogInformation("Listing raw NDI sources for {TotalMs} ms (polling every {PollMs} ms)…", totalMs, pollMs);
+        using var finder = interop.CreateFinder();
+        var seen = new SortedSet<string>(StringComparer.Ordinal);
+        var elapsed = 0;
+        while (elapsed < totalMs)
+        {
+            await Task.Delay(pollMs);
+            elapsed += pollMs;
+            foreach (var s in interop.GetCurrentSources(finder))
+            {
+                if (seen.Add(s))
+                    logger.LogInformation("  + {Source}", s);
+            }
+        }
+        logger.LogInformation("Done. {Count} unique source(s) seen in {TotalMs} ms.", seen.Count, totalMs);
+        interop.Dispose();
+        return 0;
+    }
 }