[chore]: update vscode extension recommendations (#1546)

## Summary

- Replace the VS Code Pylance recommendation with Astral's ty extension
and mark Pylance as unwanted for this workspace.
- Refresh the recommended extension list around the current project
setup: Python, Ruff, TOML, YAML recipes/workflows, Markdown, notebooks,
C++/CUDA kernels, Docker, and repo workflow helpers.
- Add inline installation guidance for installing workspace
recommendations from VS Code, the VS Code CLI, or Cursor.

## Why

The main change is to use ty instead of Pylance for editor-side Python
language support. Astral describes ty as an extremely fast Python type
checker and language server, written in Rust, and it comes from the same
toolchain family as uv and Ruff. That makes it a better fit for this
repo's modern Python tooling direction than recommending Pylance by
default.

One nuance: this PR only changes editor extension recommendations. It
does not replace the repository's configured MyPy/pre-commit checks.

## Validation

- git diff --check -- .vscode/extensions.json
- pre-commit ran during commit and passed for the staged file


<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

* **Chores**
* Updated workspace extension recommendations to include new development
tools (Ruff, Markdown linting) and reorganized the extensions list.
Added clarification comments for installation guidance to streamline the
developer setup experience.

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Signed-off-by: Shengliang Xu <shengliangx@nvidia.com>

.vscode/extensions.json

@@ -1,27 +1,38 @@
 {
-	// See https://go.microsoft.com/fwlink/?LinkId=827846 to learn about workspace recommendations.
-	// Extension identifier format: ${publisher}.${name}. Example: vscode.csharp
-	// List of extensions which should be recommended for users of this workspace.
+	// Installation:
+	// - In VS Code, open Extensions and search "@recommended" to install workspace recommendations.
+	// - From a shell, run "code --install-extension <extension-id>" for each item below.
+	// - In Cursor, use "cursor --install-extension <extension-id>" if the Cursor CLI is available.
+
+	// List of extensions recommended for this workspace.
 	"recommendations": [
-		"ms-vscode.cpptools",
-		"ms-azuretools.vscode-docker",
+		// Python development: pyproject.toml configures pytest and Ruff.
+		"ms-python.python",
+		"astral-sh.ty",
+		"charliermarsh.ruff",
+
+		// Project/config files: pyproject.toml, YAML recipes/workflows, and Markdown.
 		"tamasfe.even-better-toml",
+		"redhat.vscode-yaml",
+		"DavidAnson.vscode-markdownlint",
+
+		// Notebooks and native extensions used by examples and kernels.
+		"ms-toolsai.jupyter",
+		"ms-vscode.cpptools",
+
+		// Repo workflow helpers.
+		"ms-azuretools.vscode-docker",
 		"GitHub.copilot",
 		"GitLab.gitlab-workflow",
 		"eamodio.gitlens",
-		"VisualStudioExptTeam.vscodeintellicode",
-		"ms-toolsai.jupyter",
-		"ms-python.vscode-pylance",
-		"ms-python.python",
 		"ms-vscode-remote.remote-ssh",
 		"ms-vscode.remote-explorer",
-		"charliermarsh.ruff",
-		"redhat.vscode-yaml",
 	],
-	// List of extensions recommended by VS Code that should not be recommended for users of this workspace.
+	// List of extensions not recommended for this workspace.
 	"unwantedRecommendations": [
 		"ms-python.black-formatter",
 		"ms-python.mypy-type-checker",
+		"ms-python.vscode-pylance",
 		"ms-python.pylint",
 		"ms-python.flake8",
 	]