Increase timeout on Predbat hasn't updated time to 15 mins

[springfall2008]

No description provided.

[Copilot]

Pull Request Overview

This PR increases the timeout threshold for detecting whether Predbat is actively running from 6 minutes to 15 minutes, and fixes incorrect unit specifications in discharge rate percentage handling.

Key Changes:

• Extended the staleness check timeout from 360 seconds (6 minutes) to 900 seconds (15 minutes)
• Corrected required_unit parameter from "W" to "%" for discharge rate percentage operations

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
apps/predbat/predbat.py	Updated version to v8.26.1 and increased timeout threshold from 6 to 15 minutes in the is_running() method
apps/predbat/inverter.py	Fixed incorrect required_unit parameters for charge and discharge rate percentage operations

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}