Fix rtl text rendering (#21382)

* Fix Arabic RTL text rendering in web UI

- Add dir='auto' attributes to markdown containers and blocks
- Implement post-processing to add dir='auto' to all text elements
- Replace directional CSS properties with logical properties for proper RTL list alignment
- Ensure bidirectional text support for mixed Arabic/English content

* Clean up commented duplicate function

Remove the commented-out duplicate transformMdastNode function
that was left over from refactoring.

* Fix Arabic RTL text rendering in web UI

- Add dir='auto' attributes to markdown containers and blocks
- Implement post-processing to add dir='auto' to all text elements
- Replace directional CSS properties with logical properties for proper RTL list alignment
- Minor code formatting improvements

This ensures bidirectional text support for mixed Arabic/English content in the llama.cpp web UI.

* Implement rehype plugin for comprehensive RTL text support

- Add rehypeRtlSupport plugin that applies dir='auto' to all elements with children
- Replace DOMParser-based approach with efficient HAST tree processing
- Remove hardcoded element lists for better maintainability
- Ensure proper bidirectional text rendering for mixed RTL/LTR content

* Fix RTL text rendering with rehype plugin and cleanup

* fix: prettier formatting

tools/server/webui/src/lib/components/app/content/MarkdownContent.svelte

@@ -16,6 +16,7 @@
 	import { rehypeEnhanceLinks } from '$lib/markdown/enhance-links';
 	import { rehypeEnhanceCodeBlocks } from '$lib/markdown/enhance-code-blocks';
 	import { rehypeResolveAttachmentImages } from '$lib/markdown/resolve-attachment-images';
+	import { rehypeRtlSupport } from '$lib/markdown/rehype-rtl-support';
 	import { remarkLiteralHtml } from '$lib/markdown/literal-html';
 	import { copyCodeToClipboard, preprocessLaTeX, getImageErrorFallbackHtml } from '$lib/utils';
 	import {
@@ -101,6 +102,7 @@
 			.use(rehypeEnhanceLinks) // Add target="_blank" to links
 			.use(rehypeEnhanceCodeBlocks) // Wrap code blocks with header and actions
 			.use(rehypeResolveAttachmentImages, { attachments })
+			.use(rehypeRtlSupport) // Add bidirectional text support
 			.use(rehypeStringify, { allowDangerousHtml: true }); // Convert to HTML string
 	});
 
@@ -781,19 +783,19 @@
 	/* Lists */
 	div :global(ul) {
 		list-style-type: disc;
-		margin-left: 1.5rem;
+		margin-inline-start: 1.5rem;
 		margin-bottom: 1rem;
 	}
 
 	div :global(ol) {
 		list-style-type: decimal;
-		margin-left: 1.5rem;
+		margin-inline-start: 1.5rem;
 		margin-bottom: 1rem;
 	}
 
 	div :global(li) {
 		margin-bottom: 0.25rem;
-		padding-left: 0.5rem;
+		padding-inline-start: 0.5rem;
 	}
 
 	div :global(li::marker) {
@@ -816,8 +818,8 @@
 	/* Task lists */
 	div :global(.task-list-item) {
 		list-style: none;
-		margin-left: 0;
-		padding-left: 0;
+		margin-inline-start: 0;
+		padding-inline-start: 0;
 	}
 
 	div :global(.task-list-item-checkbox) {

tools/server/webui/src/lib/markdown/rehype-rtl-support.ts

@@ -0,0 +1,28 @@
+/**
+ * Rehype plugin to provide comprehensive RTL support by adding dir="auto"
+ * to all text-containing elements.
+ *
+ * This operates directly on the HAST tree, ensuring that all elements
+ * (including those not in a predefined list) receive the attribute.
+ */
+
+import type { Plugin } from 'unified';
+import type { Root, Element } from 'hast';
+import { visit } from 'unist-util-visit';
+
+/**
+ * Rehype plugin to add dir="auto" to all elements that have children.
+ * This provides bidirectional text support for mixed RTL/LTR content.
+ */
+export const rehypeRtlSupport: Plugin<[], Root> = () => {
+	return (tree: Root) => {
+		visit(tree, 'element', (node: Element) => {
+			if (node.children && node.children.length > 0) {
+				node.properties = {
+					...node.properties,
+					dir: 'auto'
+				};
+			}
+		});
+	};
+};