Every WarpEngine API response now carries `WarpEngine-Version`, so a client can branch on
the engine's age without a round trip to ask. Set in a before_action rather than after:
`rescue_from` never reaches an after_action, and a client needs the version most when
something came back wrong. The name lives in `WarpEngine::VERSION_HEADER`. The host's own
endpoints — the store registry — do not carry it, because they are not the engine.
A software has one pipeline, and the newest assignment now wins. Two pipelines pointing at
the same software was not an error the database caught; it was a link that silently did
nothing, with the software still showing whichever row came first. Assigning a software
another pipeline holds therefore moves it, the admin says which pipeline it was taken
from, and `Pipeline#software_taken_from` carries that for anything else that cares.
Deliberately a callback and not a unique index: rows here are soft-deleted, and a unique
index counts deleted rows, so a pipeline removed last year would block its software from
ever being linked again.
The engine is 0.4.0. The site's /stores page and its screenshot follow the client's new
name, and the shot is a fresh one showing the greyed-out titles the client now lists.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>