Improve Chromecast application handling and nullability

- Enhanced `DeviceService` to check for existing applications before accessing namespaces, launching a default media receiver if none are found.
- Updated `ChromecastStatus` and made properties `Applications`, `Volume`, and `Application` nullable for better error handling.

Author: Tapanila

SharpCaster.Console/Services/DeviceService.cs

@@ -176,7 +176,15 @@ private async Task CheckAndJoinExistingApplicationAsync()
 
         try
         {
-            var hasReceiverNamespace = _state.Client.ChromecastStatus.Application.Namespaces?.Any(ns => ns.Name == "urn:x-cast:com.google.cast.receiver") == true;
+            var application = _state.Client.ChromecastStatus.Application;
+            if (application == null)
+            {
+                AnsiConsole.MarkupLine("[dim]No existing application found. Launching Default Media Receiver...[/]");
+                await _state.Client.LaunchApplicationAsync("B3419EF5", false);
+                AnsiConsole.MarkupLine("[green]✅ Default Media Receiver launched successfully![/]");
+                return;
+            }
+            var hasReceiverNamespace = application?.Namespaces?.Any(ns => ns.Name == "urn:x-cast:com.google.cast.receiver") == true;
             // Refresh receiver status to get the most current application information
             if (hasReceiverNamespace)
             {

Sharpcaster/.editorconfig

@@ -213,4 +213,7 @@ csharp_style_prefer_not_pattern = true:suggestion
 csharp_style_prefer_extended_property_pattern = true:suggestion
 csharp_style_var_when_type_is_apparent = false:silent
 csharp_style_var_for_built_in_types = false:silent
-csharp_style_var_elsewhere = false:silent
+csharp_style_var_elsewhere = false:silent
+csharp_prefer_system_threading_lock = true:warning
+csharp_style_prefer_implicitly_typed_lambda_expression = true:suggestion
+csharp_style_prefer_unbound_generic_type_in_nameof = true:suggestion

Sharpcaster/Models/ChromecastStatus/ChromecastStatus.cs

@@ -1,5 +1,4 @@
-using System.Collections.Generic;
-using System.Collections.ObjectModel;
+using System.Collections.ObjectModel;
 using System.Linq;
 using System.Text.Json.Serialization;
 
@@ -12,7 +11,7 @@ namespace Sharpcaster.Models.ChromecastStatus
     public class ChromecastStatus
     {
         [JsonPropertyName("applications")]
-        public Collection<ChromecastApplication> Applications { get; set; }
+        public Collection<ChromecastApplication>? Applications { get; set; }
 
         [JsonPropertyName("isActiveInput")]
         public bool IsActiveInput { get; set; }
@@ -21,9 +20,9 @@ public class ChromecastStatus
         public bool IsStandBy { get; set; }
 
         [JsonPropertyName("volume")]
-        public Volume Volume { get; set; }
+        public Volume? Volume { get; set; }
 
         [JsonIgnore]
-        public ChromecastApplication Application => Applications?.FirstOrDefault();
+        public ChromecastApplication? Application => Applications?.FirstOrDefault();
     }
 }