Add platform-specific startup config files for Linux/Windows

Remove old startup config references and add startup.json.linux and startup.json.windows with default directory paths for each platform. These files are now copied to output and publish directories, and include documentation on override priority.

Jellyfin.Server/Jellyfin.Server.csproj

@@ -44,9 +44,18 @@
     <PackageReference Include="SmartAnalyzers.MultithreadingAnalyzer" PrivateAssets="All" />
   </ItemGroup>
   <ItemGroup>
-    <Content Remove="Resources\Configuration\startup.default.json" />
-    <Content Remove="Resources\Configuration\startup.linux.json" />
-    <Content Remove="Resources\Configuration\startup.windows.json" />
+    <Content Remove="startup.json.example" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <None Include="startup.json.linux">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+      <CopyToPublishDirectory>PreserveNewest</CopyToPublishDirectory>
+    </None>
+    <None Include="startup.json.windows">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+      <CopyToPublishDirectory>PreserveNewest</CopyToPublishDirectory>
+    </None>
   </ItemGroup>
 
   <ItemGroup>

Jellyfin.Server/startup.json.linux

@@ -0,0 +1,13 @@
+{
+  "_comment": "Jellyfin Startup Configuration - Linux defaults - using /var/lib/jellyfin",
+  "_note": "These paths will be used unless overridden by environment variables or command-line arguments",
+  "_priority": "Command-line args > Environment variables > This file > Built-in defaults",
+  "Paths": {
+    "DataDir": "/var/lib/jellyfin/data",
+    "ConfigDir": "/etc/jellyfin",
+    "CacheDir": "/var/cache/jellyfin",
+    "LogDir": "/var/log/jellyfin",
+    "TempDir": "/tmp/jellyfin",
+    "WebDir": "wwwroot"
+  }
+}

Jellyfin.Server/startup.json.windows

@@ -0,0 +1,13 @@
+{
+  "_comment": "Jellyfin Startup Configuration - Windows defaults - using C:/ProgramData/jellyfin",
+  "_note": "These paths will be used unless overridden by environment variables or command-line arguments",
+  "_priority": "Command-line args > Environment variables > This file > Built-in defaults",
+  "Paths": {
+    "DataDir": "C:/ProgramData/jellyfin/data",
+    "ConfigDir": "C:/ProgramData/jellyfin/config",
+    "CacheDir": "C:/ProgramData/jellyfin/cache",
+    "LogDir": "C:/ProgramData/jellyfin/log",
+    "TempDir": "C:/ProgramData/Temp/jellyfin",
+    "WebDir": "wwwroot"
+  }
+}