[CI Failure] Flaky: VS Code extension Blazor browser debugger E2E tests fail with websocket proxy launch failure and WASM root session timeouts on Linux

## Build Information

Build: https://github.com/microsoft/aspire/actions/runs/35132956836
Build error leg or test failing: Tests / Run VS Code extension E2E tests / VS Code extension E2E (Linux, browser-debugger) / `Aspire Blazor browser debugger E2E hits a managed breakpoint for standalone / hosted-global / hosted-per-page`
Pull request: #20176

## Classification Analysis

The PR only modifies Aspire.Dashboard Razor/CSS files and Directory.Packages.props; it does not touch the VS Code extension, Blazor debug adapter, or the WASM debugging proxy code exercised by these tests. All three failures in this job are timing/connectivity issues establishing the Chrome DevTools websocket proxy or waiting (up to 5 minutes) for a WASM debug session to attach, consistent with flaky CI environment/browser-launch timing rather than a functional regression caused by the PR.

## Failure Information

Test output

Failed to apply E2E control revision 1789583483915: Error: Blazor debugger launch failed: {"seq":11,"type":"response","request_seq":2,"command":"launch","success":false,"body":{"error":{"id":9240,"format":"Unable to launch browser: \"Could not open ws://localhost:43999/_framework/debug/ws-proxy?browser=ws%3A%2F%2F127.0.0.1%3A41015%2Fdevtools%2Fbrowser%2F6b0247f0-58bb-4258-92c6-4665d94a07cc\"","showUser":true}}}


Failed to apply E2E control revision 1789583483918: Error: Timed out after 299646ms waiting for Blazor WASM root session for resource 'hosted-global'. Last error: <none>.

Failed to apply E2E control revision 1789583483921: Error: Timed out after 299592ms waiting for Blazor WASM root session for resource 'hosted-per-page'. Last error: <none>.

Stack frames reference out/test-e2e/test-e2e/browserDebugger.e2e.test.js:170, helpers.js:52 (proveBlazorScenario), fixtures.js:167 (executeE2eControlCommand), assertions.js:355 (applyE2eControl).

## Description

Flaky: VS Code extension Blazor browser debugger E2E tests fail with websocket proxy launch failure and WASM root session timeouts on Linux

**Type**: flaky-test

## Occurrences

| Date | Build | Job | PR |
|------|-------|-----|----|
| 2026-09-16 | [35132956836](https://github.com/microsoft/aspire/actions/runs/35132956836) | Tests / Run VS Code extension E2E tests / VS Code extension E2E (Linux, browser-debugger) | #20176 |

Start with out/test-e2e/test-e2e/browserDebugger.e2e.test.js:170, helpers.js:52, fixtures.js:167, and assertions.js:355, then run the Linux browser-debugger E2E job to observe the websocket and WASM session failures. Done means the affected standalone, hosted-global, and hosted-per-page scenarios complete reliably without proxy launch errors or root-session timeouts.

Written by the indexing model from the issue text.