CI took about 27 minutes because one Windows job ran every step in order,
and the Linux job repeated analyze, tests, and the Rust tests. Now analyze,
two test shards, and the web build run on Linux for every change, in
parallel. The Convex, presence, client-contract, Rust bridge, and desktop
build lanes run only when a PR touches their files. Pushes, PRs into main,
and PRs that change CI still run every lane. A newer push to a PR cancels
its older run, and the desktop builds cache cargokit's compiled Rust
dependencies.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>