feat: add ==highlight== inline spans with markdownStyle.highlight

[hryhoriiK97]

What/Why?

Adds support for CommonMark-style highlight spans (==text==) to EnrichedMarkdownText, gated behind a new opt-in parser flag so existing markdown is unaffected.

Testing

Screenshot

iOS	Android

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

Adds opt-in support for CommonMark-style highlight spans (==text==) across the Enriched Markdown pipeline (parser → AST → renderers) with a new md4cFlags.highlight toggle and a new markdownStyle.highlight style bucket.

Changes:

• Extends MD4C parsing (C++ + WASM + native bridges) to emit a Highlight inline node when md4cFlags.highlight is enabled.
• Adds highlight rendering/styling on Web (<mark>), iOS (new HighlightRenderer + style config), and Android (new HighlightSpan/renderer + style config).
• Updates docs and example Storybook stories to demonstrate the new flag and style options.

Reviewed changes

Copilot reviewed 55 out of 57 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/web/types.ts	Adds Highlight to the web AST node type union.
src/web/styles.ts	Introduces highlight CSS style and wires it into buildStyles.
src/web/renderers/InlineRenderers.tsx	Adds <mark> renderer for Highlight inline nodes.
src/web/parseMarkdown.ts	Extends WASM parseMarkdown binding to pass the new highlight flag.
src/web/EnrichedMarkdownText.tsx	Plumbs md4cFlags.highlight through parsing and effect dependencies.
src/types/MarkdownStyleInternal.ts	Adds internal highlight style shape.
src/types/MarkdownStyle.ts	Adds public markdownStyle.highlight + md4cFlags.highlight docs/types.
src/normalizeMarkdownStyle.web.ts	Adds default highlight style + normalization for highlight color fallback.
src/normalizeMarkdownStyle.ts	Adds default highlight style + normalization for highlight color fallback (native).
src/native/EnrichedMarkdownText.tsx	Adds default + normalized md4cFlags.highlight for native components.
src/EnrichedMarkdownTextNativeComponent.ts	Extends codegen types with highlight style + md4cFlags.highlight.
src/EnrichedMarkdownNativeComponent.ts	Extends codegen types with highlight style + md4cFlags.highlight.
ios/utils/StylePropsUtils.h	Applies highlight colors from props into StyleConfig.
ios/utils/MarkdownExtractor.m	Extracts highlight spans back to ==...== when serializing to markdown.
ios/utils/MarkdownASTSerializer.m	Serializes highlight AST nodes as ==...==.
ios/utils/HTMLGenerator.m	Emits <mark> with highlight styles in generated HTML output.
ios/styles/StyleConfig.mm	Stores highlight colors in style config and supports copying/accessors.
ios/styles/StyleConfig.h	Declares highlight style config accessors.
ios/renderer/RendererFactory.m	Registers iOS HighlightRenderer for highlight nodes.
ios/renderer/RenderContext.m	Adds helper to resolve highlight foreground color vs block/paragraph colors.
ios/renderer/RenderContext.h	Exposes calculateHighlightColor API.
ios/renderer/HighlightRenderer.m	New renderer applying highlight foreground/background attributes.
ios/renderer/HighlightRenderer.h	New highlight renderer header + attribute name.
ios/parser/MarkdownParserBridge.mm	Bridges Highlight node type + flag into ObjC/C++ parser.
ios/parser/MarkdownASTNode.h	Adds MarkdownNodeTypeHighlight.
ios/parser/ENRMMarkdownParser.mm	Adds _highlight default/copy behavior for parser flags.
ios/parser/ENRMMarkdownParser.h	Adds highlight flag property.
ios/internals/MeasurementCache.h	Includes highlight flag + style fields in measurement cache key/hash.
ios/EnrichedMarkdownText.mm	Triggers re-render/measure when md4cFlags.highlight changes.
ios/EnrichedMarkdown.mm	Triggers re-render/measure when md4cFlags.highlight changes.
docs/STYLES.md	Documents markdownStyle.highlight and usage example.
docs/API_REFERENCE.md	Documents md4cFlags.highlight and updates defaults.
cpp/wasm/md4c_wasm.cpp	Extends WASM export signature + wires highlight flag.
cpp/wasm/ASTSerializer.cpp	Serializes C++ Highlight node type to "Highlight".
cpp/parser/MD4CParser.hpp	Adds highlight to Md4cFlags struct.
cpp/parser/MD4CParser.cpp	Enables MD_FLAG_HIGHLIGHT and maps MD_SPAN_MARK → Highlight node.
cpp/parser/MarkdownASTNode.hpp	Adds Highlight to C++ NodeType enum.
apps/example/ios/Podfile.lock	Updates iOS example pod lockfile checksums/tooling versions.
apps/example/.rnstorybook/stories/components/EnrichedMarkdownText/shared/storybookStyleBuilders.ts	Adds builder for highlight style controls.
apps/example/.rnstorybook/stories/components/EnrichedMarkdownText/shared/storybookMarkdownStyles.ts	Adds highlight control defaults/types for Storybook.
apps/example/.rnstorybook/stories/components/EnrichedMarkdownText/props/Md4cFlags.stories.tsx	Adds highlight flag toggle to md4cFlags Storybook story.
apps/example/.rnstorybook/stories/components/EnrichedMarkdownText/inline/Highlight.stories.tsx	Adds a dedicated Storybook story for highlight spans.
android/src/main/java/com/swmansion/enriched/markdown/utils/text/conversion/MarkdownExtractor.kt	Extracts highlight spans back to ==...== when serializing markdown.
android/src/main/java/com/swmansion/enriched/markdown/utils/text/conversion/HTMLGenerator.kt	Emits <mark> for highlight spans in generated HTML.
android/src/main/java/com/swmansion/enriched/markdown/utils/common/serialization/MarkdownASTSerializer.kt	Serializes highlight AST nodes as ==...==.
android/src/main/java/com/swmansion/enriched/markdown/utils/common/MarkdownViewManagerUtils.kt	Parses md4cFlags.highlight from JS props.
android/src/main/java/com/swmansion/enriched/markdown/styles/StyleConfig.kt	Adds highlight style parsing and includes it in equality/hashCode.
android/src/main/java/com/swmansion/enriched/markdown/styles/HighlightStyle.kt	New Android highlight style value object.
android/src/main/java/com/swmansion/enriched/markdown/spans/HighlightSpan.kt	New span applying highlight foreground/background without clobbering nested styles.
android/src/main/java/com/swmansion/enriched/markdown/renderer/SpanStyleCache.kt	Adds cached highlight colors + block-aware highlight foreground resolver.
android/src/main/java/com/swmansion/enriched/markdown/renderer/NodeRenderer.kt	Registers Android HighlightRenderer.
android/src/main/java/com/swmansion/enriched/markdown/renderer/HighlightRenderer.kt	New renderer that wraps children with HighlightSpan.
android/src/main/java/com/swmansion/enriched/markdown/parser/Parser.kt	Adds highlight to Android Md4cFlags.
android/src/main/java/com/swmansion/enriched/markdown/parser/MarkdownASTNode.kt	Adds Highlight node type to Android AST model.
android/src/main/java/com/swmansion/enriched/markdown/MeasurementStore.kt	Includes md4cFlags.highlight in measurement parsing/cache key inputs.
android/src/main/cpp/jni-adapter.cpp	Bridges highlight flag and node type ordinal to Java.

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[Copilot]

Pull request overview

Copilot reviewed 58 out of 60 changed files in this pull request and generated 4 comments.

[eszlamczyk]

nit/question: Personally I find string interpolation more readable here — you can see the whole tag at once rather than mentally splicing across chained .append() calls. Something like in suggested change

I get that the rest of the file uses the chained-append style for consistency, so happy to leave it for now but it might be worth a separate refactor PR to convert the other tag-assembly sites (handleBlockquote, handleList, etc.) the same way. The cost of the extra string allocation per tag should be negligible compared to the readability improvement.

Suggested change

	if (isHighlight) {
	html
	.append("<mark style=\"background-color: ")
	.append(styles.highlightBackgroundColor)
	if (styles.highlightColor != styles.paragraphColor) {
	html
	.append("; color: ")
	.append(styles.highlightColor)
	}
	html.append(";\">")
	}
	if (isHighlight) {
	val colorPart = if (styles.highlightColor != styles.paragraphColor) "color: ${styles.highlightColor};" else ""
	html.append("<mark style=\"background-color: ${styles.highlightBackgroundColor}; $colorPart\">")
	}

[hryhoriiK97]

@eszlamczyk yes, agreed! Let's keep this as it is for now, and we'll implement the refactor when we have some free bandwidth.