Consider adding PYTHONSTARTUP with shell integration to environment variable collection

[Tyriar]

Currently opening the REPL will open the default shell with a custom environment:

vscode-python/src/client/common/terminal/service.ts

Lines 82 to 86 in e90b95d

	this.terminal = this.terminalManager.createTerminal({
	name: this.options?.title || 'Python',
	env: { PYTHONSTARTUP: this.envVarScript },
	hideFromUser: this.options?.hideFromUser,
	});

And then run & .../python3 to launch it as a sub-shell:

Why not set the environment variable globally such that any python sub-shell will have shell integration? Adding this to my pwsh profile works:

$env:PYTHONSTARTUP = "/Users/tyriar/.vscode-insiders/extensions/ms-python.python-2024.13.2024080701-darwin-arm64/python_files/pythonrc.py"

[Tyriar]

@anthonykim1 are you tracking somewhere the next step for this to change setting defaults?

[anthonykim1]

@Tyriar I'm not since the default is set to true now in: https://github.com/microsoft/vscode-python/pull/24111/files#diff-7ae45ad102eab3b6d7e7896acd08c427a9b25b346470d7bc6507b6481575d519R635
Thought this was safe enough to make it true out of the gate, given how long shell integration was enabled (with shift+enter) for awhile without complains.

Should we rather start at false and then later change default to true? @Tyriar

[Tyriar]

@anthonykim1 it was previously scoped to only users that use the Start REPL comment though, right? Adding this to all terminals when the python extension is installed will massively increase the user base of the feature and also adds unsuspecting users to that list where it's critical we don't break or show an error for. I've always felt there's no rush to roll these things out slowly as the alternative can mean recovery releases and disrupting users.