Feature: Additional sensors

[rialDave]

Hey there!

I've found your integration and really liked the idea of having nowcast information in home assistant. Even tho it might be enough for some use cases to have actions/service calls to get this information, I wanted to have sensor data for my setup.

So i went and added some sensor which might make life and usage with this integration easier in my opinion:

• max precipitation (60 min): peak precipitation intensity (mm/h) in the next 60 minutes, same data as the existing service but as a live sensor. Also exposes the full per-minute forecast as a sensor attribute.
• current precipitation: intensity (mm/h) at the current minute
• next precipitation: timestamp of the next precipitation onset (skips the current event if precipitation is already active)
• precipitation until: timestamp when the current precipitation event drops below threshold (unavailable when precipitation is not active)
• precipitation active: binary sensor (on/off) based on current minute's intensity

Config / options flow:

• configurable precipitation threshold (default: 0.1 mm/h), used by the binary sensor, Next Precipitation, and Precipitation Until

I've also added translations in EN and DE when i was already on it and updated the Readme accordingly.

Full disclosure:

1. thats my first PR (please don't be rude 😅)
2. the code is authored by Claude Code, reviewed by me with basic Python knowledge. It's running on my HA for a few days now and i didn't encounter any problems or bugs yet.

(the .gitignore is just added for my PHPStorm .idea files, I didn't find a way to exclude this from the PR)

[hanneshier]

Woul love if this could be merged! @rialDave could you merge this feature to your main branch in the meantime? So your modifications can be installed via HACS if this does not get merged