fix: report today's total rainfall in !wx, not the last hour

[sg]

Problem

!wx <city> reported Rain: 0.0in even after inches had fallen. The script read Open-Meteo's current.precipitation, which is only the preceding hour's total — so once the rain stops it reads 0, regardless of earlier rainfall. Not an Open-Meteo bug; the wrong field/window was requested.

Live confirmation for Bee Cave (30.30854, −97.94501): current.precipitation = 0.0in while daily.precipitation_sum[today] = 0.425in (7 rainy hours).

Fix

commands/wx.py now requests daily=precipitation_sum with timezone=auto and reports today's accumulated, local-day total as "Rain" (with an n/a fallback). Dropped precipitation from the current block.

Verified live:

• !wx bee cave → Rain: 0.425in (was 0.0in)
• !wx Austin US → Rain: 0.862in

Caveat

precipitation_sum is a modeled gridded estimate — much better than the old 0.0, but it can still undercount very localized heavy downpours vs a physical gauge (that's what !pws is for).