Linkable chat prompts/instructions/modes using vscode:// links

[aeschli]

Fixes https://github.com/microsoft/vscode-copilot/issues/12944

[bpasero]

Are we not thinking about a way to ask the user for confirmation? This seems to trigger a non-trivial action (other than for example the one I added to show the chat view).

Prior art for when we open files/folders:

vscode/src/vs/code/electron-main/app.ts

Lines 132 to 135 in f82b740

	private static readonly SECURITY_PROTOCOL_HANDLING_CONFIRMATION_SETTING_KEY = {
	[Schemas.file]: 'security.promptForLocalFileProtocolHandling' as const,
	[Schemas.vscodeRemote]: 'security.promptForRemoteFileProtocolHandling' as const
	};

[bpasero]

As per my comment.

[bpasero]

Just read in chat that you indicate a prompt is shown where to put the file, can you share an example? And can the user cancel and no action is performed?

[aeschli]

I added a confirmation dialog:

[bpasero]

I would use a setting and name it similar to the existing ones we have, something like security.promptForPromptProtocolHandling

[aeschli]

@bpasero Can we discuss this in a follow-up issue?
I don't think we need to hold up the PR for that. I'd like @digitarald to be able to try this out tomorrow if it works for our use case.

[bpasero]

@aeschli I opened #252530