Minor plan improvements, Whatif EDF, bug fixes

What's Changed

Planning improvements

• fix(plan): stop tweak and second pass regressing the plan by @springfall2008 in #4402
• fix(plan): score plan selection on the plan as optimised, not as clipped by @springfall2008 in #4403
• fix(plan): add a charge step margin to the clip charge slot compares by @springfall2008 in #4411

Bug fixes

• fix(hass): don't misdetect an existing install as new on a transient predbat.status read failure by @chalfontchubby in #4409
• feat(config): retry validate_config() after a failure, self-healing (#4379) by @chalfontchubby in #4394
• fix(inverter): stop spurious "REST failed to setExportTarget" warnings by @springfall2008 in #4413

Whatif improvements

• Fix pre-commit cspell failure for EDF Go Electric tariff token by @springfall2008 with @Copilot in #4412
• feat(whatif): edf tariffs by @Easen in #4406

New Contributors

• @Easen made their first contribution in #4406

Full Changelog: v8.47.2...v8.47.3