Align nightly devcontainer with the polyglot template

[Mitch Denny (mitchdenny)]

Summary

Port the changes from microsoft/aspire-devcontainer#10 while retaining the nightly repository's Aspire team dogfooding setup.

• Use Ubuntu 24.04 with Node.js LTS, OS-provided Python, uv, and .NET 10 installed as peer features; add ESLint, Python, and Pylance editor support.
• Configure HTTPS through aspire certs trust --non-interactive and SSL_CERT_DIR.
• Preserve the nightly CLI installer (-q dev), retry logic, Codespaces prebuild cache cleanup, Azure/Kubernetes tooling and extensions, host requirements, and existing NuGet feeds.
• Retain a small Dockerfile to supply ICU independently of the standalone SDK, explicitly expose the nightly CLI on PATH, and skip NuGet cache cleanup when the SDK is omitted.
• Add fresh-start/restart lifecycle CI for Python/React, C#/Blazor, and TypeScript without a standalone .NET SDK, including team CLI probes and failure diagnostics.
• Preserve Dockerfile/build-context paths in generated test configurations and copy the repository's NuGet configuration into the smoke projects' parent directory.
• Update polyglot ignore rules and nightly setup/customization documentation.

Validation

• Built the full and SDK-free nightly containers locally on Linux ARM64 through Docker.
• Passed all three smoke scenarios on fresh startup and after stopping/reopening the containers.
• Confirmed the SDK-free bootstrap skips NuGet cleanup and dotnet remains absent from PATH before and after running Aspire.
• Passed all five configuration-helper regression tests on both host Node.js and the container's Node.js 24.
• Checked workflow YAML, embedded shell syntax, configuration invariants, and ignore rules.

Local validation does not cover hosted Linux x64 CI, VS Code extension installation/debugging, browser rendering, IDE port forwarding, or actual Azure/Kubernetes deployments.