An image alone on its line, inside a paragraph with other lines, rendered inline
on iOS and web: the library only treats sole-child paragraph images as blocks,
and with hardSoftBreaks every newline is a break node. The source adaptation now
gives such images their own paragraph (keeping quote markers and list
indentation), so all platforms render them as blocks with image margins. Images
sharing a line with text stay inline. Verified through the library's md4c wasm
parser in the renderer tests.