feat: Proof-Carrying Memory ledger core (substrate-v2 P1) #66

Job	Run time
Assert zero runtime dependencies	5s
Dependency review	7s
Lint & format (Biome)	18s
Test (Node 22)	13s
Test (Node 18)	18s
Test (Node 20)	16s
ShellCheck	6s
	1m 23s

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