Fix CI gates and accelerate Rust builds

[ExtraBinoss]

Summary

• fix the native lifecycle coverage flake and the iOS ActivityKit closure returns
• validate SemVer against the intended major release and install Linux API-check dependencies
• isolate crate packaging from shared Cargo targets and fetch dependencies before the offline archive check
• use sccache for compiler outputs while keeping Cargo registry caching small and reliable
• start independent CI jobs immediately and build the four WASM bundles with bounded concurrency

Validation

• ./scripts/linux-hidden-display.sh env ARGUI_NATIVE_TESTS=1 CARGO_BUILD_JOBS=2 BINARYEN_CORES=2 CARGO_INCREMENTAL=0 nice -n 15 ./scripts/quality.sh
• workspace coverage: 88.23% branches, 93.76% functions, 94.56% lines, 93.65% regions
• python3 -m unittest discover -s tests/scripts
• pnpm --dir website typecheck
• pnpm --dir website test
• actionlint v1.7.12

No [PUBLISH] marker is present, so this cannot publish v0.3.

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