v0.15.0

Changes

• ECMap / ECRadar: Replace WMS-fetched legend with locally generated horizontal legends for all three radar layers (rain, snow, precip_type), matching the Environment Canada weather map style
• ECMap / ECRadar: Bundle DejaVu Sans font for legend labels and timestamp overlay, replacing the old bitmap font
• ECMap: Fix composite cache key to include language so EN/FR frames are cached independently