Improve nuget installation output

AGENTS.md

@@ -29,7 +29,7 @@ The test runner is **Microsoft.Testing.Platform** with the **xUnit v3** runner (
 
 ### Test-suite behavior to know about
 
-- Heavy Roslyn/integration tests share `[Collection(nameof(RoslynServices))]` and run **serially** on purpose: `MSBuildLocator.RegisterDefaults()` and the loader's `AssemblyLoadContext.Resolving` hooks (attached to the process-global Default ALC by `AssemblyLoadContextHook` and never detached) are process-global, not per-`RoslynServices`. The full suite is ~2 minutes.
+- Heavy Roslyn/integration tests share `[Collection(nameof(RoslynServices))]` and run **serially** on purpose: the loader's `AssemblyLoadContext.Resolving` hooks (attached to the process-global Default ALC by `AssemblyLoadContextHook` and never detached) are process-global, not per-`RoslynServices`. The full suite is ~2 minutes. (`MSBuildLocator.RegisterDefaults()` is also process-global, but a `[ModuleInitializer]` in `TestAssemblyInitializer` runs it once at assembly load, so it's no longer the reason for the collection — and tests that only needed MSBuildLocator, like `NugetPackageInstallerTests`, can now run in isolation.)
 - Some tests spawn `dotnet build` / MSBuild subprocesses (solution/project references) and a few touch the network (NuGet install). These are the slow ones and can occasionally be flaky.
 - The inspect-feature integration tests (`InspectorRoundTripTests`, `InspectorCancellationTests`, `RemoteEditorServicesTests`, `InspectorServerProtocolTests`, `RemoteReadEvalPrintLoopTests`) **launch a real hooked child process** — the interactive PrettyPrompt loop itself cannot be driven without a TTY, so `RemoteReadEvalPrintLoopTests` stubs `IPrompt` (like `ReadEvalPrintLoopTests`) and everything below it is real. Two more inspect suites run in-process without a child: `InspectorEngineTests` hosts the real engine + Roslyn inside the test process, and `InspectorTransportTests` exercises the real OS pipe/socket transport (note: the Windows pipe uses zero-byte buffers, so a write rendezvouses with the peer's read — keep the read pending while writing).
 

CSharpRepl.Services/IConsoleService.cs

@@ -2,6 +2,8 @@
 // License, v. 2.0. If a copy of the MPL was not distributed with this
 // file, You can obtain one at https://mozilla.org/MPL/2.0/.
 
+using System;
+using System.Threading.Tasks;
 using PrettyPrompt.Consoles;
 using PrettyPrompt.Highlighting;
 using Spectre.Console;
@@ -20,6 +22,13 @@ public interface IConsoleService
     // The underlying Spectre console that provides e.g. color coded / wrapped output.
     protected IAnsiConsole Ansi { get; }
 
+    /// <summary>
+    /// Whether the console is an interactive terminal. False when output is redirected (piped, <c>--eval</c>,
+    /// captured by a tool), where cursor movement and live displays (e.g. status spinners) can't render and
+    /// must degrade to plain text. Mirrors <c>!Console.IsOutputRedirected</c>; overridable so it can be faked in tests.
+    /// </summary>
+    bool IsInteractive => !Console.IsOutputRedirected;
+
     /// <summary>Width, in characters, of the console buffer — for layout/wrapping math.</summary>
     int BufferWidth => PrettyPromptConsole.BufferWidth;
 
@@ -36,6 +45,17 @@ public interface IConsoleService
     void Write(string text) => Ansi.Write(text);
     void Write(FormattedString text) => PrettyPromptConsole.Write(text);
 
+    /// <summary>Writes a line of Spectre.Console markup. During a live display (e.g. a status spinner) it renders above the live region.</summary>
+    void WriteMarkupLine(string markup) => Ansi.MarkupLine(markup);
+
+    /// <summary>
+    /// Runs <paramref name="action"/> while displaying an animated status spinner labelled <paramref name="status"/>
+    /// (Spectre markup), returning the action's result. Output written to this console during the action - e.g. via
+    /// <see cref="WriteMarkupLine"/> - is rendered above the live spinner and remains after it disappears.
+    /// </summary>
+    Task<T> RunWithStatusAsync<T>(string status, Spinner spinner, string color, Func<Task<T>> action)
+        => Ansi.Status().Spinner(spinner).SpinnerStyle(Style.Parse(color)).StartAsync(status, _ => action());
+
     void WriteLine(string text) => Ansi.WriteLine(text);
     void WriteLine() => Ansi.WriteLine();
     void WriteLine(FormattedString text) => PrettyPromptConsole.WriteLine(text);