- Backend tests run with `cargo nextest run --profile ci`: one process
per test, a 180s per-test timeout (src-tauri/.config/nextest.toml),
and no fail-fast. The WSL2 nightly uses it too, still one test at a
time and with the same selection as the old `--skip database::`, so a
hung test is killed instead of eating the whole job.
- Integration tests shared one fixed test home, and each process wiped
it on startup. Under nextest they ran concurrently and failed en
masse, so tests/support.rs now picks a directory per
NEXTEST_TEST_GLOBAL_SLOT. Plain `cargo test` keeps the old directory.
- Swatinem/rust-cache replaces the hand-rolled actions/cache step. It
caches dependencies only, not the cc-switch crate that is rebuilt
every run, and keys on OS, rustc version and Cargo.lock. The WSL2 CI
job and the nightly share the `backend` key but only restore it, so
their lib-only builds never save over the full Windows cache.
- Quote the $GITHUB_OUTPUT redirect that shellcheck flagged.
