refactor(launcher): replace LauncherFlowCoordinator with LaunchPipeline and slim App shell

Co-authored-by: Cursor <cursoragent@cursor.com>

LanMountainDesktop.Launcher/Startup/HostLaunchModels.cs

@@ -0,0 +1,77 @@
+using System.Diagnostics;
+using LanMountainDesktop.Launcher.Models;
+using LanMountainDesktop.Shared.Contracts.Launcher;
+
+namespace LanMountainDesktop.Launcher.Startup;
+
+internal enum HostStartMode
+{
+    ShellExecute,
+    Direct
+}
+
+internal sealed record HostStartAttempt(
+    HostStartMode StartMode,
+    bool ProcessCreated,
+    Process? Process,
+    bool ExitedEarly,
+    int? ExitCode,
+    string? FailureReason,
+    string? PackageRoot,
+    string? WorkingDirectory,
+    string? Arguments)
+{
+    public int? ProcessId => Process?.Id;
+
+    public static HostStartAttempt Started(HostStartMode startMode, Process process, HostLaunchPlan plan) =>
+        new(
+            startMode,
+            true,
+            process,
+            false,
+            null,
+            null,
+            plan.PackageRoot,
+            plan.WorkingDirectory,
+            HostLaunchPlanBuilder.FormatArgumentsForLog(plan.Arguments));
+
+    public static HostStartAttempt EarlyExit(HostStartMode startMode, Process process, int exitCode, HostLaunchPlan plan) =>
+        new(
+            startMode,
+            true,
+            process,
+            true,
+            exitCode,
+            null,
+            plan.PackageRoot,
+            plan.WorkingDirectory,
+            HostLaunchPlanBuilder.FormatArgumentsForLog(plan.Arguments));
+
+    public static HostStartAttempt StartFailed(HostStartMode startMode, string failureReason, HostLaunchPlan? plan = null) =>
+        new(
+            startMode,
+            false,
+            null,
+            false,
+            null,
+            failureReason,
+            plan?.PackageRoot,
+            plan?.WorkingDirectory,
+            plan is null ? null : HostLaunchPlanBuilder.FormatArgumentsForLog(plan.Arguments));
+}
+
+internal sealed record HostLaunchOutcome(
+    LauncherResult Result,
+    Process? Process,
+    LauncherResult? ImmediateResult,
+    Dictionary<string, string> Details)
+{
+    public static HostLaunchOutcome FromResult(LauncherResult result) =>
+        new(result, null, result.Success ? result : null, result.Details);
+
+    public static HostLaunchOutcome FromImmediateResult(LauncherResult result) =>
+        new(result, null, result, result.Details);
+
+    public static HostLaunchOutcome FromProcess(Process process, LauncherResult result, Dictionary<string, string> details) =>
+        new(result, process, null, details);
+}