Collapse the Data sources section by default in the About dialog

[DocGerd]

Context

In the About / info dialog (opened via the info button), the changelog ("What's new") is presented in a collapsed Disclosure by default, but the Data sources / attribution section is shown expanded. For visual consistency and a tidier dialog, the data-sources section should also start collapsed.

Desired behavior

• The "Data sources" section starts collapsed by default, matching the changelog's Disclosure pattern (reuse the existing Disclosure primitive — see UI/UX: modernize the app's look & feel to a state-of-the-art standard #64).
• Exception — license-required attribution: any credit a data source's license requires to be displayed must remain satisfied. Audit per source before collapsing:
  • OpenStreetMap / basemap + seamarks (ODbL) — attribution must be "reasonably calculated to inform". Note the map already shows "© OpenStreetMap contributors" via the MapLibre attribution control, so collapsing the dialog copy is likely fine as long as the on-map attribution stays.
  • Open-Meteo wind (CC-BY 4.0) — requires attribution; confirm it stays discoverable.
  • Any other bundled source (Salona 45 polars, harbor list, depth mask).
• If a license genuinely requires an always-visible credit that lives only in this dialog, keep that credit visible (or move it to the persistent on-map attribution) rather than collapsing it.

Acceptance criteria

• Data-sources section collapsed by default via the shared Disclosure primitive.
• Audit each data source's license; note in the PR which (if any) must stay visible and why.
• Confirm the on-map MapLibre attribution independently satisfies OSM/ODbL + basemap requirements regardless of the dialog's collapsed state.
• de/en i18n for any new expand/collapse label (no hardcoded strings).
• No chart-authority copy introduced.

References

• Changelog Disclosure pattern (CHANGELOG.md (Keep a Changelog) + changelog visible in the app #131); Disclosure primitive (UI modernization UI/UX: modernize the app's look & feel to a state-of-the-art standard #64).
• MapView ATTRIBUTION — keep one anchor per accessible name (don't duplicate the OSM link; CLAUDE.md Chart features: buoys, beacons and other seamarks on the map (and optionally in routing) #7 lesson).