[seaspotter]

Fixt das Problem das ich mit #4153 reingebracht habe:
Leeren Store beim Zyklus-Split nicht mehr fälschlich publizieren

#3785 (comment)

[Copilot]

🟢 Approval recommended

All reviewed changes are covered by regression tests and no unresolved blocking issues were identified.

No open issues 🎉

What changed in this PR

This hotfix prevents empty forecast data from being published before the first successful provider fetch, while preserving the existing today/tomorrow cycle split.

Changes:

• Defers ForecastValueStore state initialization until forecast data is available.
• Safely ignores missing state in LoggingValueStore.
• Adds regression coverage for pre-fetch updates and publication behavior.

File	Description
packages/​modules/​common/​store/​_forecast.py	Prevents an empty forecast state from being published before the first fetch.
packages/​modules/​common/​store/​_forecast_test.py	Tests missing-state handling and safe no-op publishing.
packages/​modules/​common/​configurable_forecast_test.py	Verifies updates remain safe before the first forecast fetch.

_{Review effort: Lite}