Station CRUD via the API previously mutated the scraper's in-memory
station_mapping only, so changes were lost on restart (and the systemd
service auto-restarts).
- Extract the 130-line hardcoded station_mapping into bundled defaults at
src/data/stations.json; the scraper loads from a runtime-writable config
file (STATION_CONFIG_PATH, default stations.json) and falls back to the
bundled defaults to seed it.
- Add scraper.save_stations() with an atomic temp-file + os.replace write.
- create/update/delete station endpoints now persist and roll back the
in-memory change if the write fails; re-raise HTTPException so persistence
errors surface as real 500s instead of being swallowed.
- Backend-agnostic (works for the VictoriaMetrics deployment, which has no
relational stations table). Runtime stations.json is gitignored.
Also clears pre-existing flake8 debt in water_scraper_v3.py (unused imports,
long lines, duplicate logging import) and dedupes the User-Agent to
Config.USER_AGENT.
grabowski
4bc3d82773