Fix race condition on soc values in web ui

[springfall2008]

Maybe root cause of: #4016

[Copilot]

Pull request overview

This PR addresses an SoC display inconsistency in the Web UI (suspected recurrence of issue #4016) by reducing the chance of readers observing partially-updated multi-inverter totals while fetch_inverter_data() is summing values.

Changes:

• Initialize additional inverter-related aggregate fields in PredBat.reset() so they have safe defaults.
• Refactor Execute.fetch_inverter_data() to accumulate inverter totals in locals and only publish to self.* after the loop completes.
• Avoid restoring self.soc_kw in Output.calculate_yesterday() (prevents overwriting newer SoC values from other update paths).

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
apps/predbat/predbat.py	Adds default initialization for additional reserve/limit aggregate fields during reset.
apps/predbat/output.py	Stops restoring self.soc_kw at the end of calculate_yesterday().
apps/predbat/execute.py	Accumulates inverter totals in locals and publishes after the loop to reduce mid-sum races.