Adds @vitest/coverage-v8 (catalog-pinned), a test:coverage script wired
through turbo (inputs + coverage/** output), and coverage thresholds set
to a floor measured on main (lines 18 / funcs 10 / branches 10 / stmts
17 against current 19.3/11.4/11.7/18.9). Ratchet upward as tests grow.
Adapts the coverage config from @BenSheridanEdwards's fork; the multi-job
CI fan-out from that branch was intentionally left out.
Co-authored-by: Ben Sheridan-Edwards <BenSheridanEdwards@users.noreply.github.com>
Adds a `tauri` task to turbo.json with dependsOn ["^build"] so that
desktop#tauri automatically triggers web#build first via the workspace
dependency graph. The tauriScript routes tauri-action through turbo
rather than invoking tauri directly, eliminating the need for an
explicit build step.
