"Current File" option in the project picker #1395
Description
The problem: When you click the status bar and any projects exist, pickProjectMany() shows only registered projects — no escape hatch. Per-file environment selection is completely lost.
The fix — add a special "Current File" item to the project picker:
When the user clicks the status bar, and the active editor has a Python file open, inject a separator + two extra items at the top of the pickProjectMany quick pick:
"$(file) Set for current file" — Selects an environment scoped to just the active file's URI. This is the old default behavior. It skips project selection entirely and goes straight to the environment picker, passing the file URI.
"$(add) Add current file as project..." — Creates a new project rooted at the file's parent directory (using the existing addPythonProjectCommand with quickCreate), then immediately opens the environment picker for that new project. This promotes the file into the project system in one click.