fix(map): adapt map height to adjacent content

[Paul-AUB]

🤔 What

• The map height on entrance and cavity pages now adapts to the height of the adjacent content panel
• Removes the empty space that appeared below the map when the information panel was taller than 400px

Closes #1426

🤷‍♂️ Why

When the adjacent content (localisation, characteristics, vigilance points, data quality…) exceeds 400px, the map container was left with a visible blank area underneath, creating an unbalanced layout.

🔍 How

Single-line change in MapContainer.jsx: replaced the fixed height: 400px with height: 100%; min-height: 400px.

The parent HalfSplitContainer already uses align-items: stretch (flex row on desktop), so both columns grow to the same height. Switching the map wrapper to height: 100% lets it fill that stretched height rather than staying capped at 400px.

On mobile (stacked column layout), the parent has no fixed height, so height: 100% would collapse — min-height: 400px acts as the floor, preserving the existing mobile behaviour.

🔗 Related API PR

N/A

🧪 Testing

Open an entrance page where the right-hand panel is tall (e.g. https://grottocenter.org/ui/entrances/2772) and verify there is no blank space below the map.

📸 Previews

[urien]

C'est parfait. Merci @Paul-AUB