ci(release): build Linux artifacts as static musl binaries (#447)

Build Linux release artifacts as statically linked musl binaries for x86_64 and aarch64, update packaging and updater handling, and document the reduced runtime requirements.

Keep release version preparation locked without refreshing dependencies or committing Cargo.lock.

Closes #440

just/build.just

@@ -17,6 +17,11 @@ build_crates_release:
 build_release target features="":
   cargo build --locked --release --target {{ target }} {{ features }}
 
+# Build a static musl Linux release binary in a pinned Alpine container
+[group('build')]
+build_musl target:
+  dist/release/build_musl.sh {{ target }}
+
 # Package an already-built Linux release as a Debian package
 [group('build')]
 package_deb target: