FR: support for multiple html-based output types - specifically email + dashboard

[kmasiello]

A Quarto doc on Connect can support multiple output formats such as a html-email output and typst option, e.g.,

format:
  email:
    toc: true
    toc-location: left

  typst:
    toc: true

however, because email is html based, use of another html-based output (such as dashboard) is in conflict and will not render.

FR: enable both dashboard and email format types to be specified, or more generally, support multipe html-based outputs in a document.

[cscheid]

(Tagging this as projects because to fix this, we need to fix the management of intermediate files, and that goes through projects)

[mcanouil]

• Epic: Execution Planner #6518

[cderv]

@cscheid @mcanouil I don't think this is just a conflict in rendering as other issues we may have. So not just an Execution Planner kind of things.

The question is here: How can the email feature be available for Dashboard too ?

Email format is created internally the same way as Dashboard format

quarto-cli/src/format/email/format-email.ts

Lines 11 to 19 in d39cb2f

	registerWriterFormatHandler((format) => {
	switch (format) {
	case "email":
	return {
	format: emailFormat(),
	pandocTo: "html",
	};
	}
	});

quarto-cli/src/format/dashboard/format-dashboard.ts

Lines 277 to 285 in d39cb2f

	registerWriterFormatHandler((format) => {
	switch (format) {
	case "dashboard":
	return {
	format: dashboardFormat(),
	pandocTo: "html",
	};
	}
	});

So email will be using html as the pandoc to format.

Email format brings the email feature, and I think for it to work with Dashboard it is more than just execution planner topic.