chore(licence): normalise to MPL-2.0 + CC-BY-SA-4.0 (canonical pair) … #96

Job	Run time
Build release artifacts (macos-latest, x86_64-apple-darwin, vsh-macos-x64)	1m 15s
Lint (clippy + rustfmt)	41s
Cross-compile (x86_64-unknown-linux-musl)	2m 5s
Test Features (--all-features)	1m 10s
Cross-compile (aarch64-unknown-linux-gnu)	1m 55s
Build documentation	31s
Test (nightly on macos-latest)	3h 1m 39s
Test MSRV (1.88.0)	35s
Test Features (--features echidna)	1m 14s
Build release artifacts (ubuntu-latest, x86_64-unknown-linux-gnu, vsh-linux-x64)	1m 23s
Test (stable on ubuntu-latest)	3h 32m 46s
Test (stable on macos-latest)	3h 5m 34s
Test (nightly on ubuntu-latest)	3h 59m 31s
Test (beta on macos-latest)	3h 3m 6s
Test Features (--no-default-features)	1m 16s
Test (beta on ubuntu-latest)	3h 43m 30s
	20h 38m 11s

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