Automatic environment picks are saved like explicit ones; new .venv ignored #1894

Problem: When the extension picks an environment automatically, it saves the pick in the same per-workspace state as a user's explicit choice, and later discovery never revisits it. In a project whose only venv was tools/.venv, creating the project's own .venv (for example python -m venv .venv in a terminal) leaves tools/.venv selected, even after a reload. A fresh profile on the same folder picks .venv. The log reports the old pick as source: autoDiscovery.

Environment: Windows 11, VS Code 1.140.0, Python Environments main @ 52f6ace.

Before: .venv is created from outside VS Code, and the selection stays on tools/.venv:

The same folder in the same profile after reopening (left), and in a fresh profile (right). The tooltips show the selected interpreter:

Reopen, same profile	Fresh profile

Cause:

• applyInitialEnvironmentSelection stores the auto-discovered environment with setEnvironment(folder.uri, env, false), meant as "cache only".
• setEnvironmentCore still calls manager.set(scope, environment). VenvManager.set then persists it with setVenvForWorkspace, the same slot an explicit pick uses. SysPythonManager does the same (sysPythonManager.ts:207).
• On the next refresh and startup, loadEnvMap and the fast path read the saved path first, so it wins over discovery.

Impact:

• A new .venv is ignored in any project that already has another venv under it (for example one found through the default */.venv search path).
• Improvements to automatic selection, such as fix: prefer a project's own .venv over nested venvs (Fixes #1878) #1880, don't reach workspaces that already saved an automatic pick.

Suggested fix: Record whether a saved selection was chosen by the user. Keep using an automatic one for the fast startup path, but run automatic selection again after discovery and replace the saved pick if the result differs. Explicit choices stay as they are.

Steps to verify fix:

1. Create a folder with only tools/.venv and a main.py, open it, and verify tools/.venv is selected.
2. Run python -m venv .venv in the folder from a terminal.
3. Verify the status bar switches to .venv within a few seconds.
4. Reload the window; verify .venv stays selected.
5. Explicitly select tools/.venv with Python: Set Project Environment and reload; verify the explicit choice is kept.

Found by Copilot