marketplace: remove preview status (#1660)

## Summary

- remove the extension-level Marketplace preview designation
- remove stale README language about the completed rollout
- retain labels for individual features that are still experimental

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: eleanorjboyd

README.md

@@ -1,6 +1,4 @@
-# Python Environments (preview)
-
-> **Note:** The Python Environments icon may no longer appear in the Activity Bar due to the ongoing rollout of the Python Environments extension. To restore the extension, add `"python.useEnvironmentsExtension": true` to your User settings. This setting is temporarily necessary until the rollout is complete!
+# Python Environments
 
 ## Overview
 
@@ -11,8 +9,6 @@ The Python Environments extension for VS Code helps you manage Python environmen
 -   ✅ Create activated terminals
 -   🖌️ Add and create new Python projects
 
-> **Note:** This extension is in preview, and its APIs and features are subject to change as the project evolves.
-
 > **Important:** This extension requires version `2024.23`, or later, of the Python extension (`ms-python.python`).
 
 ## Features

package.json

@@ -4,7 +4,6 @@
     "description": "Provides a unified python environment experience",
     "version": "1.37.0",
     "publisher": "ms-python",
-    "preview": true,
     "engines": {
         "vscode": "^1.110.0-20260204"
     },