Conflicts resolved:
- sw.js: bumped CACHE_NAME to dienstplan-pro-v4 (was v3 + v2). Both
variants.js and image-import.js are in ASSETS.
- storage.js: kept STORAGE_KEY_DUTIES + STORAGE_KEY_VACATION (Feature B)
alongside STORAGE_KEY_OPENROUTER_KEY/MODEL + DEFAULT_MODEL (Feature A).
- styles.css: appended Feature B variants/vacation/date-stepper rules
after Feature A modal/key rules; both blocks coexist.
`let app` at top level does not create a window property, so the
DOMContentLoaded handler in image-import.js found window.app undefined
and never instantiated window.imageImporter. Clicking the Bild-Import
button then showed the 'Bild-Import nicht verfuegbar' toast.
Set window.app explicitly after construction.
