EXPERIMENTAL: Add tutorial testing workflows integrated with Sphinx docs #3649

Job	Run time
check-links	57s
smoke (amaranth-lang/amaranth-stdio)	52s
smoke (amaranth-lang/amaranth-boards)	40s
document	48s
test (3.11)	2m 48s
smoke (amaranth-lang/amaranth-soc)	56s
test (3.13)	3m 52s
test (3.12)	4m 9s
test (pypy-3.9)	5m 41s
test (3.9)	2m 28s
test (3.10)	2m 21s
test (pypy-3.10)	4m 49s
test (3.14-dev)	1m 54s
publish-docs	0s
publish-docs-dev	0s
required	2s
publish-release	0s
publish-package	0s
publish-schemas	0s
	32m 17s

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