fix(60): declare disabled-channel and no-playout as Unavailable preview causes

GetPreview keyed only on StreamingMode + JWT, so a disabled channel or one
with no playout was declared Available and then failed confusingly (404 from
IptvController, or an indefinitely-blocking manifest request). Extend it to
take isEnabled + playoutCount and check JWT, then disabled, then no-playout,
before falling back to the existing mode-based rules; order is documented
in a comment. Also corrects a stale comment in ChannelPreviewResponseModel.cs
that claimed a C# string generates a TypeScript union (it does not).

ErsatzTV.Application/Channels/Mapper.cs

@@ -114,7 +114,7 @@ internal static class Mapper
             channel.ShowInEpg,
             playoutCount,
             GetLogoUrl(channel),
-            GetPreview(channel.StreamingMode, channel.Number, iptvJwtEnabled));
+            GetPreview(channel.StreamingMode, channel.Number, iptvJwtEnabled, channel.IsEnabled, playoutCount));
 
     internal static ResolutionViewModel ProjectToViewModel(Resolution resolution) =>
         new(resolution.Height, resolution.Width);
@@ -183,8 +183,17 @@ internal static class Mapper
     internal static ChannelPreviewResponseModel GetPreview(
         StreamingMode streamingMode,
         string channelNumber,
-        bool iptvJwtEnabled)
+        bool iptvJwtEnabled,
+        bool isEnabled,
+        int playoutCount)
     {
+        // Precedence among the three Unavailable causes (checked in this order; the first match wins):
+        //   1. JWT enabled       — a host-wide auth configuration; nothing the operator can fix per-channel.
+        //   2. channel disabled  — an explicit operator choice; IptvController 404s a disabled channel, so
+        //                          preview must not even try.
+        //   3. no playout        — the channel could theoretically play once scheduled, but a manifest
+        //                          request against it blocks indefinitely today; catch it before that happens.
+        //
         // /iptv/* is gated by ConditionalIptvAuthorizeFilter only when JWT is configured, and the
         // "jwt" scheme does not accept the SPA's ctv-session cookie. Nothing mints a JWT for the
         // SPA today, so preview cannot run at all in that configuration.
@@ -196,6 +205,22 @@ internal static class Mapper
                 "IPTV JWT authentication is enabled");
         }
 
+        if (!isEnabled)
+        {
+            return new ChannelPreviewResponseModel(
+                ChannelPreviewAvailability.Unavailable,
+                null,
+                "Channel is disabled");
+        }
+
+        if (playoutCount == 0)
+        {
+            return new ChannelPreviewResponseModel(
+                ChannelPreviewAvailability.Unavailable,
+                null,
+                "Channel has no playout");
+        }
+
         return streamingMode switch
         {
             StreamingMode.HttpLiveStreamingSegmenter or StreamingMode.HttpLiveStreamingDirect =>

ErsatzTV.Core/Api/Channels/ChannelPreviewResponseModel.cs

@@ -9,8 +9,10 @@ namespace ErsatzTV.Core.Api.Channels;
 /// SPA would mean keying behavior off the human-readable StreamingMode label.
 /// </remarks>
 public record ChannelPreviewResponseModel(
-    // One of ChannelPreviewAvailability's values. A plain string (not an enum) so the generated
-    // TypeScript is a string union the SPA can switch on directly.
+    // One of ChannelPreviewAvailability's values. A plain string (not a C# enum), which keeps the
+    // OpenAPI schema simple, but the tradeoff is that the generated TypeScript types this as a bare
+    // `string`, not a literal union — the SPA hand-maintains its own `ChannelPreviewAvailability`
+    // union (web/src/api/channels.ts) and narrows against it, rather than getting one for free.
     string Availability,
     // Rooted, directly-usable HLS manifest URL; null when Availability is Unavailable.
     string? ManifestUrl,

ErsatzTV.Tests/Application/Channels/ChannelPreviewTests.cs

@@ -13,7 +13,8 @@ public class ChannelPreviewTests
     [TestCase(StreamingMode.HttpLiveStreamingDirect)]
     public void HlsModes_Are_Available_With_Plain_Manifest_Url(StreamingMode mode)
     {
-        ChannelPreviewResponseModel result = Mapper.GetPreview(mode, "12.1", iptvJwtEnabled: false);
+        ChannelPreviewResponseModel result =
+            Mapper.GetPreview(mode, "12.1", iptvJwtEnabled: false, isEnabled: true, playoutCount: 1);
 
         result.Availability.ShouldBe("Available");
         result.ManifestUrl.ShouldBe("/iptv/channel/12.1.m3u8");
@@ -24,7 +25,8 @@ public class ChannelPreviewTests
     [TestCase(StreamingMode.TransportStreamHybrid)]
     public void TransportStream_Modes_Are_ForcedHlsOnly(StreamingMode mode)
     {
-        ChannelPreviewResponseModel result = Mapper.GetPreview(mode, "12.1", iptvJwtEnabled: false);
+        ChannelPreviewResponseModel result =
+            Mapper.GetPreview(mode, "12.1", iptvJwtEnabled: false, isEnabled: true, playoutCount: 1);
 
         result.Availability.ShouldBe("ForcedHlsOnly");
         result.ManifestUrl.ShouldBe("/iptv/channel/12.1.m3u8?mode=segmenter");
@@ -37,18 +39,53 @@ public class ChannelPreviewTests
     [TestCase(StreamingMode.TransportStreamHybrid)]
     public void Jwt_Enabled_Makes_Every_Mode_Unavailable(StreamingMode mode)
     {
-        ChannelPreviewResponseModel result = Mapper.GetPreview(mode, "12.1", iptvJwtEnabled: true);
+        ChannelPreviewResponseModel result =
+            Mapper.GetPreview(mode, "12.1", iptvJwtEnabled: true, isEnabled: true, playoutCount: 1);
 
         result.Availability.ShouldBe("Unavailable");
         result.ManifestUrl.ShouldBeNull();
         result.UnavailableReason.ShouldBe("IPTV JWT authentication is enabled");
     }
 
+    [Test]
+    public void Disabled_Channel_Is_Unavailable()
+    {
+        ChannelPreviewResponseModel result = Mapper.GetPreview(
+            StreamingMode.HttpLiveStreamingSegmenter,
+            "12.1",
+            iptvJwtEnabled: false,
+            isEnabled: false,
+            playoutCount: 1);
+
+        result.Availability.ShouldBe("Unavailable");
+        result.ManifestUrl.ShouldBeNull();
+        result.UnavailableReason.ShouldBe("Channel is disabled");
+    }
+
+    [Test]
+    public void Zero_Playout_Count_Is_Unavailable()
+    {
+        ChannelPreviewResponseModel result = Mapper.GetPreview(
+            StreamingMode.HttpLiveStreamingSegmenter,
+            "12.1",
+            iptvJwtEnabled: false,
+            isEnabled: true,
+            playoutCount: 0);
+
+        result.Availability.ShouldBe("Unavailable");
+        result.ManifestUrl.ShouldBeNull();
+        result.UnavailableReason.ShouldBe("Channel has no playout");
+    }
+
     [Test]
     public void Channel_Number_Is_Used_Verbatim_In_The_Manifest_Url()
     {
-        ChannelPreviewResponseModel result =
-            Mapper.GetPreview(StreamingMode.HttpLiveStreamingSegmenter, "7", iptvJwtEnabled: false);
+        ChannelPreviewResponseModel result = Mapper.GetPreview(
+            StreamingMode.HttpLiveStreamingSegmenter,
+            "7",
+            iptvJwtEnabled: false,
+            isEnabled: true,
+            playoutCount: 1);
 
         result.ManifestUrl.ShouldBe("/iptv/channel/7.m3u8");
     }

ErsatzTV.Tests/Controllers/OpenApiSerializerContractTests.cs

@@ -156,7 +156,7 @@ public class OpenApiSerializerContractTests
         true,
         2,
         "/iptv/logos/logo.png",
-        Mapper.GetPreview(StreamingMode.HttpLiveStreamingSegmenter, "1", false));
+        Mapper.GetPreview(StreamingMode.HttpLiveStreamingSegmenter, "1", false, true, 2));
 
     private static string FindOpenApiDocument()
     {