feat!: Hugrs now keep a `ExtensionRegistry` with their requirements (… #2862

Job	Run time
Check for changes in Python files	4s
check python 3.10	12s
Check serialization schema	13s
check python 3.13	28s
Build HUGR binary	1m 10s
test python 3.10	22s
test python 3.13	48s
Required checks 🐍	1s
	3m 18s

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