feat(.claude): add prompts — migration spec, Pumpkin actions, LazyLoc… #1

Job	Run time
miri	5m 35s
clippy/stable	37s
cargo-careful	1m 46s
format/stable	11s
native-backend/stable	50s
docs/nightly	33s
cross_test/i686-unknown-linux-gnu/stable	1m 18s
nostd/thumbv6m-none-eabi/stable	15s
cross_test/s390x-unknown-linux-gnu/stable	1m 18s
Pass MSRV values to other jobs	4s
tests/1.64.0	1m 48s
tests/stable	1m 29s
tests/beta	1m 42s
blas-msrv	29s
conclusion	0s
	17m 55s

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