feat(hpc): complete Pumpkin shopping list — 5 gap fills + JIT noise codegen #12

Job	Run time
format/stable	14s
cross_test/s390x-unknown-linux-gnu/stable	1m 25s
cross_test/i686-unknown-linux-gnu/stable	1m 17s
native-backend/stable	52s
Pass MSRV values to other jobs	3s
nostd/thumbv6m-none-eabi/stable	16s
clippy/stable	30s
miri	0s
docs/nightly	0s
cargo-careful	0s
blas-msrv	22s
tests/beta	1m 31s
tests/1.64.0	1m 39s
tests/stable	1m 25s
conclusion	0s
	9m 34s

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