encryption: sealed channel (X448 + HKDF-SHA384), and neutralize dalek's SIMD by cfg #690

Job	Run time
Pass MSRV values to other jobs	2s
format/stable	21s
clippy/1.95.0	52s
tier4-avx512-check	38s
neon-simd/parity-qemu	52s
native-backend/stable	8m 32s
hpc-stream-parallel/rayon	1m 35s
nostd/thumbv6m-none-eabi/stable	26s
wasm-simd/parity-node	59s
docs/nightly	0s
cross_test/${{ matrix.target }}/${{ matrix.rust }}	0s
cargo-careful	0s
tests/beta	11m 25s
tests/stable	11m 1s
tests/1.95.0	11m 43s
blas-msrv	59s
miri	-6s
nightly-simd-polyfill	-8s
conclusion	0s
	49m 11s

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