Poll the open api-v3.thaiwater.net public endpoints (rain_24h,
waterlevel_load), filter to the Ping basin, and persist to new
hii_rain_stations/hii_rainfall and hii_wl_stations/hii_waterlevel tables
(auto-created; sqlite/postgresql/mysql). Water levels stay in their own
tables since HII reports m MSL from a different station set; rid_code
maps mirrors like ridhydro_P.1 to P.1 and offset_msl converts MSL to
gauge datum. Runs every scraping cycle in web-api and continuous modes
(hourly cadence even during 1-minute RID retry), one-shot via
--collect-hii; docs/DATA_SOURCES.md catalogs all probed endpoints.
