## Why
The monolithic CI workflow is a frequent merge-conflict hotspot.
Splitting cohesive domains into same-repository reusable workflows keeps
one centrally filtered entry point while letting Rust, desktop,
relay/PostgreSQL, client, and security CI evolve independently.
## What
- Keep `ci.yml` as the only push/pull-request orchestrator with
unchanged concurrency and path detection.
- Move 18 execution jobs into five `workflow_call`-only domain workflows
without changing their runners, steps, matrices, caches, artifacts,
permissions, or timeouts.
- Keep the relay artifact producer with desktop integration, the
complete PostgreSQL lane, and relay E2E consumers.
- Preserve all 12 existing required GitHub Actions contexts through
lightweight top-level compatibility gates, so the repository ruleset
does not need to change.
- Update the Rust-cache contract to follow Unit Tests into
`_ci-rust.yml`.
## Risk Assessment
CI-only change with moderate workflow-orchestration risk. The main risks
are reusable-workflow output propagation, skip behavior, and visible
check naming; the old required names remain explicit top-level jobs, and
the draft will stay open until an exact-head GitHub Actions run and
independent review are complete.
Generated with Codex
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Signed-off-by: Luke Tornquist <tornquist@squareup.com>
Signed-off-by: tornquist <tornquist@squareup.com>
