fix: soft markdown line breaks

[eszlamczyk]

What/Why?

Fixes #541

Soft Markdown line breaks (a single \n inside a paragraph) rendered as visual line breaks on native, unlike
standard CommonMark/GFM renderers which collapse them to a space.

The shared C++ parser mapped both MD_TEXT_SOFTBR and MD_TEXT_BR to NodeType::LineBreak. Instead of appending a literal space in the parser (which would destroy information that downstream logic depends on - display-math block promotion, editor round-trips), this PR introduces a dedicated NodeType::SoftBreak and lets each consumer decide:

• Read-only renderers (iOS, Android, web): SoftBreak renders as a space; LineBreak (hard break: trailing or \) keeps rendering as a visual break.
• Parser post-processing: isSeparatorNode accepts SoftBreak, so display math on its own line inside a paragraph is still promoted to a block.
• Input: Android InputParser maps SoftBreak → \n so the editor stays WYSIWYG and value round-trips are lossless (iOS input works on raw text and needed no change).
• AST serializers (table copy-as-markdown): SoftBreak → \n, LineBreak → \ + newline (CommonMark hard-break syntax), so hard breaks no longer degrade to soft breaks on serialize→parse cycles.
• LaTeX/alt-text extractors now emit a space for break nodes (previously $$a\nb$$ extracted as ab). SoftBreak is appended last in every enum - both Android JNI bridges map C++ NodeType to Kotlin by ordinal (guarded by the static_assert in ParserJni.cpp, now SoftBreak == 30).

Known behavior change

text\n![img](url) on Android now renders the image inline instead of block. iOS already rendered it inline (its block check tests for \n while LineBreak renders U+2028), so platforms are now consistent - but Android users relying on that layout will see a difference. Standalone images (![img] as its own paragraph) are
unaffected.

Testing

Unit: two new render tests in CommonMarkRendererTest (soft break → space, hard break → newline); full standalone suite.

Manual: these exact strings hit the combinations most likely to regress (parser post-processing and renderer heuristics key off break nodes, so they're the flaky spots):

1. Soft break (the issue repro):
   keep taking your medications as prescribed, and we'll begin tracking your\nblood sugar and blood pressure → single wrapped paragraph, no forced break after "your".
2. Hard breaks still work (both syntaxes):
   line one \nline two (two trailing spaces) and line one\\nline two (trailing backslash) → visible line break within one paragraph.
   2.1. Pagragraph vs Hard break:
   line1\n\nline2 → two paragraphs with paragraph margin between them; line1\\\nline2 → one paragraph, so the lines are separated by line height only (no paragraph margin).
3. Display math promotion (most fragile - exercises isSeparatorNode):
   • text before\n$$x^2$$\ntext after → math must still render as its own centered block, text split around it
   • $$x^2$$ alone → block (unchanged)
   • a $$x^2$$ b (same line) → stays inline (unchanged)
4. Multi-line math span: $$a +\nb$$ → typesets a + b; previously the break was dropped (ab).
5. Image after soft break (intentional change): some text\n![img](https://...) → image renders inline on both
   platforms now (was block on Android). ![img](https://...) alone in a paragraph → still block with block styling
   (maxHeight/aspectRatio/resizeMode).
6. Lazy continuations: - item\n continued and > quote\ncontinued → continuation joins with a space inside the item/quote.
7. Code unaffected: fenced block with real newlines renders unchanged; inline `code\nspan` renders with a space (md4c handles both before the AST — should be identical to before).
8. Input round-trip (Android especially): set value={"line1\nline2"} on EnrichedMarkdownTextInput → editor shows two lines; type/edit and confirm onChangeMarkdown output re-renders identically (breaks must not collapse into spaces after an edit cycle).
9. Table copy-as-markdown: copy a table via the selection menu → output re-parses to the same table.

PR Checklist

• Code compiles and runs on iOS
• Code compiles and runs on Android
• Updated documentation/README if applicable
• Ran example app to verify changes
• E2E tests are passing
• Required E2E tests have been added (if applicable)

[Copilot]

Pull request overview

This PR introduces a distinct SoftBreak AST node to differentiate CommonMark soft line breaks from hard line breaks, and updates renderers/serializers across Web, iOS, Android, and core C++ to render/serialize them appropriately.

Changes:

• Add SoftBreak to the AST/node-type enums/unions and propagate it through platform bridges/serializers.
• Render soft breaks as spaces while keeping hard breaks as explicit line breaks (<br />, \n, or markdown hard-break syntax in serializers).
• Add Android UI tests covering soft-break vs hard-break rendering behavior.

Reviewed changes

Copilot reviewed 25 out of 26 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
packages/react-native-enriched-markdown/src/web/utils.ts	Treat SoftBreak/LineBreak as whitespace when extracting plain text.
packages/react-native-enriched-markdown/src/web/types.ts	Add SoftBreak to NodeType and update AST node docs.
packages/react-native-enriched-markdown/src/web/renderers/InlineRenderers.tsx	Add SoftBreak renderer and register it in inlineRenderers.
packages/react-native-enriched-markdown/ios/utils/MarkdownASTSerializer.m	Differentiate serialization of hard breaks vs soft breaks.
packages/react-native-enriched-markdown/ios/renderer/RendererFactory.m	Render SoftBreak as a space in attributed output.
packages/react-native-enriched-markdown/ios/renderer/ENRMMathInlineRenderer.m	Treat breaks as spaces when extracting inline LaTeX.
packages/react-native-enriched-markdown/ios/renderer/ENRMImageRenderer.m	Treat breaks as spaces when building image text/alt-like content.
packages/react-native-enriched-markdown/ios/parser/MarkdownParserBridge.mm	Bridge C++ SoftBreak node type to ObjC enum.
packages/react-native-enriched-markdown/ios/parser/MarkdownASTNode.h	Add MarkdownNodeTypeSoftBreak to the ObjC node-type enum.
packages/react-native-enriched-markdown/android/src/math/java/com/swmansion/enriched/markdown/renderer/MathInlineRenderer.kt	Treat soft/hard breaks as spaces when extracting LaTeX.
packages/react-native-enriched-markdown/android/src/main/java/com/swmansion/enriched/markdown/utils/common/serialization/MarkdownASTSerializer.kt	Differentiate serialization of hard breaks vs soft breaks.
packages/react-native-enriched-markdown/android/src/main/java/com/swmansion/enriched/markdown/renderer/SoftBreakRenderer.kt	New renderer to output a space for SoftBreak.
packages/react-native-enriched-markdown/android/src/main/java/com/swmansion/enriched/markdown/renderer/NodeRenderer.kt	Register SoftBreak renderer in the Android renderer factory.
packages/react-native-enriched-markdown/android/src/main/java/com/swmansion/enriched/markdown/parser/MarkdownASTNode.kt	Add SoftBreak to the Android node-type enum.
packages/react-native-enriched-markdown/android/src/main/java/com/swmansion/enriched/markdown/input/formatting/InputParser.kt	Treat SoftBreak similarly to LineBreak during plain-text extraction for input parsing.
packages/react-native-enriched-markdown/android/src/main/cpp/jni-adapter.cpp	Map C++ SoftBreak to the correct Kotlin enum ordinal.
packages/core/cpp/wasm/ASTSerializer.cpp	Add stringification support for SoftBreak in WASM serializer.
packages/core/cpp/parser/MD4CParser.cpp	Emit SoftBreak vs LineBreak nodes from md4c and treat soft breaks as separators.
packages/core/cpp/parser/MarkdownASTNode.hpp	Add SoftBreak to core C++ NodeType.
packages/android-enriched-markdown/ui/src/test/java/com/swmansion/enriched/markdown/test/TestAstFactory.kt	Add factory helpers for softBreak() and lineBreak().
packages/android-enriched-markdown/ui/src/test/java/com/swmansion/enriched/markdown/CommonMarkRendererTest.kt	Add tests for soft-break-as-space and hard-break-as-newline.
packages/android-enriched-markdown/ui/src/main/java/com/swmansion/enriched/markdown/renderer/SoftBreakRenderer.kt	New UI renderer for SoftBreak.
packages/android-enriched-markdown/ui/src/main/java/com/swmansion/enriched/markdown/renderer/NodeRenderer.kt	Register SoftBreak renderer in UI renderer factory.
packages/android-enriched-markdown/parser/src/main/java/com/swmansion/enriched/markdown/parser/MarkdownASTNode.kt	Add SoftBreak to parser module node-type enum.
packages/android-enriched-markdown/parser/src/main/cpp/jni/ParserJni.cpp	Update JNI enum-sync assertion for new node type.

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[hryhoriiK97]

Looks good overall! One minor nit below.

[hryhoriiK97]

Nit: Since MarkdownASTNode.content is String (non-nullable, defaults to ""), both isNullOrEmpty() and !! are unnecessary here. While you're already touching this function, could simplify to:

private fun extractLatex(node: MarkdownASTNode): String {
    if (node.content.isNotEmpty()) return node.content
    return node.children.joinToString("") { child ->
      when (child.type) {
        MarkdownASTNode.NodeType.SoftBreak, MarkdownASTNode.NodeType.LineBreak -> " "
        else -> child.content
      }
    }
}