Migrate GerbilManager.sln to slnx format

- Generated GerbilManager.slnx via dotnet sln migrate (SDK 10.0.300)
- Removed legacy GerbilManager.sln after verified build
- Updated .vscode/tasks.json references to the new file

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.vscode/tasks.json

@@ -7,7 +7,7 @@
             "type": "process",
             "args": [
                 "build",
-                "${workspaceFolder}/GerbilManager.sln",
+                "${workspaceFolder}/GerbilManager.slnx",
                 "/property:GenerateFullPaths=true",
                 "/consoleloggerparameters:NoSummary;ForceNoAlign"
             ],
@@ -19,7 +19,7 @@
             "type": "process",
             "args": [
                 "publish",
-                "${workspaceFolder}/GerbilManager.sln",
+                "${workspaceFolder}/GerbilManager.slnx",
                 "/property:GenerateFullPaths=true",
                 "/consoleloggerparameters:NoSummary;ForceNoAlign"
             ],
@@ -33,7 +33,7 @@
                 "watch",
                 "run",
                 "--project",
-                "${workspaceFolder}/GerbilManager.sln"
+                "${workspaceFolder}/GerbilManager.slnx"
             ],
             "problemMatcher": "$msCompile"
         },

GerbilManager.sln

@@ -1,25 +0,0 @@
-
-Microsoft Visual Studio Solution File, Format Version 12.00
-# Visual Studio Version 17
-VisualStudioVersion = 17.5.002.0
-MinimumVisualStudioVersion = 10.0.40219.1
-Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "GerbilManagerWebAPI", "GerbilManagerWebAPI\GerbilManagerWebAPI.csproj", "{48875578-7112-4F6F-A4C0-F1E7637B513D}"
-EndProject
-Global
-	GlobalSection(SolutionConfigurationPlatforms) = preSolution
-		Debug|Any CPU = Debug|Any CPU
-		Release|Any CPU = Release|Any CPU
-	EndGlobalSection
-	GlobalSection(ProjectConfigurationPlatforms) = postSolution
-		{48875578-7112-4F6F-A4C0-F1E7637B513D}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-		{48875578-7112-4F6F-A4C0-F1E7637B513D}.Debug|Any CPU.Build.0 = Debug|Any CPU
-		{48875578-7112-4F6F-A4C0-F1E7637B513D}.Release|Any CPU.ActiveCfg = Release|Any CPU
-		{48875578-7112-4F6F-A4C0-F1E7637B513D}.Release|Any CPU.Build.0 = Release|Any CPU
-	EndGlobalSection
-	GlobalSection(SolutionProperties) = preSolution
-		HideSolutionNode = FALSE
-	EndGlobalSection
-	GlobalSection(ExtensibilityGlobals) = postSolution
-		SolutionGuid = {7F573F67-6F28-4056-8D14-0E04C8C54B7E}
-	EndGlobalSection
-EndGlobal

GerbilManager.slnx

@@ -0,0 +1,3 @@
+<Solution>
+  <Project Path="GerbilManagerWebAPI/GerbilManagerWebAPI.csproj" />
+</Solution>