Render Leaflet content blocks as Svelte components instead of converting to markdown. Handles BlobRef/CID class instances via JSON round-trip serialisation that converts them to plain POJOs before SvelteKit dehydration, then replaces blob refs with PDS URLs for image rendering. Components: LeafletBlocks (dispatcher), LeafletFacets (inline formatting), LeafletImage, LeafletCode, LeafletMath, LeafletEmbed, LeafletWebsiteCard, LeafletButton, LeafletBskyPost. Falls back to markdown rendering when blocks are unavailable.