flow-testlisted

## Procedure 0. Resolve external context per `rules/external-context.md`, using the tester agent for lookups. Delegate the procedure below (steps 1 onward, through Stop) to the tester agent (Agent tool, subagent_type: tester, foreground), passing the resolved arguments from step 0. It executes every step itself and reports results; relay its returned summary. 1. Get the scratch directory via `scratch-dir.sh`. Identify the test runner from the repo context your startup produced (`agent-context.sh`). 2. Load the `test-patterns` skill and the patterns skill matching the detected stack (`react-patterns`, `django-patterns`, etc.) when relevant to the change. 3. Identify what changed via `git diff HEAD` and `git status`. Scope testing to the delta. 4. For each changed function, component, or endpoint: - Check if tests already exist. If yes, read them and extend. - If no, create a new test file mirroring source path. 5. Scale test depth to criticality before writing anything: - Business rules, auth, payment, and security boundaries get the full coverage below. - A thin wrapper, a single-caller internal helper, or straightforward display logic gets a happy-path test only - stop there, do not apply the rest of this checklist for its own sake. For anything above that bar, write tests that verify behavior, not implementation, and cover: - Happy path - At least one negative or edge case per public surface - Boundary conditions specific to the change (null, emp