__CACHE_VERSION__ (sw.js) and __WEBUI_VERSION__ (index.html) are
functionally identical — both resolve to quote(WEBUI_VERSION, safe='')
at request time. Two names exist for historical reasons (different files
added at different times).
Rename __CACHE_VERSION__ → __WEBUI_VERSION__ in:
- static/sw.js (CACHE_NAME + VQ constant + comment)
- api/routes.py (substitution string)
- tests/test_pwa_manifest_sw.py (all assertions)
Single canonical name. No behavior change — same ?v=vX.Y.Z query strings
on the same URLs.