[CI] Flaky: DotNetWatchTest.DotNetWatch on iOS — timed out waiting for the app to start

## Flaky Test Report (automated CI post-mortem)

**Test:** `Xamarin.Tests.DotNetWatchTest.DotNetWatch(iOS,False,False)`
**Platform:** iOS (simulator)
**Category:** Flaky (app launch timeout)
**Period:** 2026-07-01 → 2026-07-06

### Summary

`DotNetWatchTest.DotNetWatch` on iOS intermittently fails with a launch timeout across **unrelated PRs**. The app is built successfully (only a `Settings.plist deprecated` warning) but the harness never sees it start:

```
Timed out waiting for the app to start. Output:
dotnet watch 🔥 Hot reload enabled. …
dotnet watch 💡 Press Ctrl+R to restart.
Determining projects to restore...
All projects are up-to-date for restore.
… warning : The settings file '…/maui/Settings.plist' is deprecated, and will be ignored. …
```

### Occurrences

| PR | Build | Date | Branch | Direct link |
|---------|----------|------------|----------|-------------|
| #25893 | 14540529 | 2026-07-01 | net11.0 | [logs](https://devdiv.visualstudio.com/DevDiv/_build/results?buildId=14540529&view=logs&j=8cda949e-c02b-5944-aa3c-d0414112a761&t=d923409d-5e5b-5971-f9ce-12c6c7f37805) |
| #25918 | 14573434 | 2026-07-06 | net11.0 | [logs](https://devdiv.visualstudio.com/DevDiv/_build/results?buildId=14573434&view=logs&j=8cda949e-c02b-5944-aa3c-d0414112a761&t=d923409d-5e5b-5971-f9ce-12c6c7f37805) |

**Total:** 2 unrelated PRs (both targeting `net11.0`).

### Classification

Identified as **flaky** because:
- It appeared across 2 unrelated PRs (dependency-update / R2R hashing) that don't touch `dotnet watch`.
- The failure is a launch timeout ("Timed out waiting for the app to start"), which is characteristic of simulator-launch flakiness rather than a build/logic error.

**Note:** so far only observed on `net11.0` PR builds; if it also shows up on `main` this may warrant a closer look at whether it's net11.0-specific. A separate variant ("Build failed before the app could start.") was seen for the MacCatalyst configuration on the dependency-update branches and is tracked separately if it recurs.

---
*This issue was automatically generated by CI post-mortem analysis.*

Start with Xamarin.Tests.DotNetWatchTest.DotNetWatch(iOS,False,False) and compare the linked CI logs from PRs #25893 and #25918, focusing on the simulator launch and harness timeout. Done means identifying the intermittent launch failure and making the iOS test start reliably in CI without the timeout.

Written by the indexing model from the issue text.