feat: support Android and iOS simulator startup profiling in maui profile

[simonrozsival]

Closes #54

Summary

This PR adds a new maui profile startup flow for collecting startup traces from MAUI apps.

The goal is to make startup profiling easy to use from the CLI: build the app, launch it on the selected target, collect the trace, and save the result in a format you can inspect right away.

How to use it

Interactive:

maui profile startup

Similarly to dotnet run, this will show pickers for the TFM, target device and the output format.

Android:

maui profile startup \
  --project MyApp.csproj \
  --framework net11.0-android \
  --device <device-id> \
  --duration 00:00:10 \
  --format nettrace \
  --output ./artifacts/startup.nettrace

iOS simulator:

maui profile startup \
  --project MyApp.csproj \
  --framework net11.0-ios \
  --device <simulator-udid> \
  --duration 00:00:10 \
  --format speedscope \
  --output ./artifacts/startup.speedscope.json

What this PR adds

• maui profile startup support for MAUI app startup traces
• Android support
• iOS simulator support
• nettrace and speedscope output options
• cleaner device routing and trace collection behavior
• improved handling for startup trace output and failure cases

Notes

• This is focused on the startup-tracing command experience itself.
• The command defaults to a Release build.
• Physical iOS devices and Mac Catalyst are not being presented as fully covered in this PR.

[Copilot]

Pull request overview

Adds an Android-first maui profile workflow to the CLI, including a build-time injected startup marker helper and orchestration of dotnet-dsrouter + dotnet-trace for startup tracing output (nettrace / speedscope).

Changes:

• Introduces a new profile top-level CLI command with Android device selection, Release-by-default builds, and trace collection orchestration.
• Adds a new Microsoft.Maui.StartupProfiling helper package plus MSBuild injection assets to auto-register an EventSource and emit a startup-complete marker.
• Improves CLI error presentation by printing captured native/tool output when available, and extends ProcessRunner to remove inherited environment variables.

Reviewed changes

Copilot reviewed 15 out of 15 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
src/Cli/Microsoft.Maui.StartupProfiling/StartupProfilingMarker.cs	Adds public marker API, module initializer, diagnostics logging, and exit-control channel logic.
src/Cli/Microsoft.Maui.StartupProfiling/StartupProfilingEventSource.cs	Adds EventSource provider and events used for stopping-event integration.
src/Cli/Microsoft.Maui.StartupProfiling/README.md	Documents helper package usage and environment variables.
src/Cli/Microsoft.Maui.StartupProfiling/Microsoft.Maui.StartupProfiling.csproj	New packable helper library project for the injected marker.
src/Cli/Microsoft.Maui.Cli/Utils/ProcessRunner.cs	Adds support for removing inherited environment variables before process start.
src/Cli/Microsoft.Maui.Cli/Program.cs	Registers the new profile command at the CLI root.
src/Cli/Microsoft.Maui.Cli/Output/SpectreOutputFormatter.cs	Displays NativeError details under CLI errors when present.
src/Cli/Microsoft.Maui.Cli/Microsoft.Maui.Cli.csproj	References the helper project and ships MSBuild injection assets alongside the tool.
src/Cli/Microsoft.Maui.Cli/Errors/ErrorCodes.cs	Adds a new diagnostics tooling error code.
src/Cli/Microsoft.Maui.Cli/Commands/ProfileCommand.cs	Implements the maui profile command, device/TFM/format resolution, and trace/dsrouter orchestration.
src/Cli/Microsoft.Maui.Cli/Build/MauiStartupProfilingInjection.targets	MSBuild targets to inject the helper assembly/source and Android env vars into the app build.
src/Cli/Microsoft.Maui.Cli/Build/MauiStartupProfiling.AutoInitialize.cs	Injected bootstrap that detects first UI readiness and signals startup complete.
src/Cli/Microsoft.Maui.Cli.UnitTests/ProfileCommandTests.cs	Adds unit tests for option defaults, argument building, and resolver behaviors.
src/Cli/Cli.slnf	Adds the new helper project to the CLI solution filter.
MauiLabs.slnx	Adds the new helper project to the repo solution.

[jonathanpeppers]

Simplification suggestions for the profiling commands:

1. Use dotnet-trace --dsrouter android|android-emu|ios|ios-sim instead of manually launching dotnet-dsrouter as a separate process. This should allow removing DotnetDsrouterRunner.cs, ProfileTransportConfiguration, the server-server/server-client branching in ResolveProfileTransport(), dsrouter PID tracking, and the StartTraceAfterLaunch retry logic that differs between Android and iOS.

2. Drop -p:AndroidEnableProfiler=true — the code already passes -p:EnableDiagnostics=true (cross-platform) in AppendDiagnosticArguments, so the Android-specific property in BuildLaunchArguments is redundant.

3. Use -p:Device={device.Id} instead of the platform-specific -p:AdbTarget=-s {device.Id} (Android) and -p:_DeviceName=:v2:udid={device.Id} (iOS). -p:Device is cross-platform and initializes the platform-specific properties automatically.