feat: Operation and constructor declarations in `hugr-model` #2402

Job	Run time
Check for changes in Python files	3s
check python 3.10	11s
Check serialization schema	14s
Build HUGR binary	48s
check python 3.13	27s
test python 3.10	20s
test python 3.13	29s
Required checks 🐍	1s
	2m 33s

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