document parallel test gate

ai/backend-context.md

@@ -131,6 +131,9 @@ intentionally unclaimed; the built-in health endpoint is `/up`.
 - Run the focused PHPUnit test while developing.
 - Use `just backend-types-check` for Larastan and `just backend-test` for the
   full PHPUnit suite during iteration.
+- The completion gate runs `backend-test-unit` and `backend-test-feature` as
+  concurrent processes. This is safe because each process owns its own
+  in-memory SQLite database.
 - Fix failures caused by the change. Report unrelated baseline failures
   precisely rather than expanding scope silently.
 - The shared `just test-all` command is the required completion gate. Focused

ai/frontend-context.md

@@ -95,6 +95,10 @@ backend and does not proxy the frontend.
 
 - Cypress is configured under `cypress/` and runs through `npm run test:e2e`
   or `just frontend-cypress-run`.
+- Every Cypress spec must appear in exactly one `frontend_specs_*` group in
+  the root `justfile`. The completion gate runs those groups concurrently,
+  and its `cypress-spec-coverage` job rejects ungrouped, duplicate, or missing
+  specs. Keep `frontend-cypress-run` for whole-suite iteration.
 - Prefer the cheapest test seam that proves the behavior. Cypress covers
   routing, browser forms, authentication flows, request wiring, and responsive
   behavior.

ai/shared.md

@@ -223,12 +223,16 @@ gate passes against that worktree:
 3. Run the complete gate from the worktree root:
 
    ```sh
-   direnv exec "$(git rev-parse --show-toplevel)" just test-all
+   JUST_JOBS=4 direnv exec "$(git rev-parse --show-toplevel)" just test-all
    ```
 
 4. Do not hand-assemble a substitute from focused commands. `test-all` runs
-   frontend format and lint checks, frontend type checking, Larastan, the
-   production build, PHPUnit, and Cypress in fail-fast order.
+   one pool of 13 jobs: frontend format, lint, type, build, and Cypress
+   groups; Larastan; the PHPUnit Unit and Feature suites; and the Cypress
+   spec coverage guard. Jobs report as they finish, failed output is buffered
+   and printed at the end, and every job runs even after another job fails.
+   `JUST_JOBS` limits concurrency and defaults to 4. Use 2 when resources are
+   constrained or 1 for a serial debugging run.
 5. Everything must pass before completion. Report exact baseline or
    environmental failures rather than hiding them.
 6. If the stack was started only for validation, stop it when finished: