/measurements/history/{code} accepts optional start/end date params that
override the hours window (end date inclusive). The dashboard history
card gains from/to date inputs beside the quick-range dropdown —
explicit dates win, changing the dropdown clears them. All user-facing
'PostgreSQL history' labels renamed to 'Station history'.
New endpoints GET /api/hii/rainfall/latest and /api/hii/waterlevel/latest
serve the latest per-station rows from the hii_* tables. The map gains a
TWA-style rain layer: circle markers binned by TMD 24-h classes (blues
for light/moderate/heavy, site amber/red for very-heavy/extreme), with a
legend block and show/hide toggle. The ThaiWater sensor panel now
prefers the DB-backed HII feed (no API key required, 97+ stations,
ThaiWater storage-percent situation colors, gauge-datum conversion via
offset_msl) and falls back to the live /sensors/thaiwater passthrough.