Fix component bugs across hooks, elements, form, layout, editors and utils

- Hooks: per-instance timers in useReady; cleanup for useIntersectionObserver;
  useWebSocket no longer reconnects after unmount/refresh, drains the queue
  and dispatches non-JSON messages
- Modal/Popover/Dropdown: onClose only on close, Escape to close, no stray
  DOM props, hooks before early return, scrollbar-aware positioning,
  top-left/top-right dropdown positions
- Elements: Toast/Search/StarRating per-instance timers, Pagination labels
  and empty state, Breadcrumbs titles, LinkList dividers/props, segment-wise
  active-link matching (new utils/link-matches-path), Table object cells
- Form: Select with a default option is changeable, Input clear notifies
  controlled parents and copy works on textareas, Checkbox random label,
  NumberInputButtons runaway interval, upload prop/spread fixes
- Layout: Button disabled while loading, Stack gap and Span truncate via
  inline styles, Img fallbackImageSrc, className/JSDoc fixes
- Editors/MDX/AI: TinyMCE id/cleanup/stale handler/duplicate scripts,
  AceEditor debounce, markdown heights and frontmatter regex, last
  assistant message, AIPromptBlock prompt ref
- Utils: fetchApi headers/FormData/fetchOptions/no mutation, base64 file
  names and read errors, slugify underscore trim, serializeQuery zero values
- Tests for fetchApi, link matching, slugify and serializeQuery
- AGENTS.md updated for the package layout

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/mdx/markdown/MarkdownEditor.tsx

@@ -65,9 +65,10 @@ export default function MarkdownEditor({
             {sideBySide ? (
                 <Row
                     className={twMerge(
-                        `w-full grid xl:grid-cols-2 gap-6 max-h-[${maxHeight}]`,
+                        "w-full grid xl:grid-cols-2 gap-6",
                         "overflow-auto",
                     )}
+                    style={{ maxHeight }}
                 >
                     <MarkdownEditorComponent
                         setValue={setValue}
@@ -81,9 +82,7 @@ export default function MarkdownEditor({
                     />
                 </Row>
             ) : (
-                <Stack
-                    className={twMerge(`w-full max-h-[${maxHeight}] h-full`)}
-                >
+                <Stack className="w-full h-full" style={{ maxHeight }}>
                     {preview ? (
                         <MarkdownEditorPreviewComponent
                             value={value}

src/mdx/markdown/MarkdownEditorComponent.tsx

@@ -21,8 +21,7 @@ export default function MarkdownEditorComponent({
                 setValue(newValue);
             }}
             wrapperProps={{
-                style: { height: maxHeight },
-                className: `max-h-[${maxHeight}]`,
+                style: { height: maxHeight, maxHeight },
             }}
             placeholder="## Write Some markdown ..."
             fontSize="14px"

src/mdx/markdown/MarkdownEditorPreviewComponent.tsx

@@ -38,8 +38,9 @@ export default function MarkdownEditorPreviewComponent({
             try {
                 // const { data, content } = matter(value);
 
+                // Strip leading front matter only (not `---` rules in the body)
                 const parsedValue = value
-                    .replace(/---([^(---)]+)---/, "")
+                    .replace(/^\s*---\r?\n[\s\S]*?\r?\n---[ \t]*(\r?\n|$)/, "")
                     .trim();
 
                 serialize(parsedValue, {
@@ -62,10 +63,15 @@ export default function MarkdownEditorPreviewComponent({
             <Border
                 {...wrapperProps}
                 className={twMerge(
-                    `w-full max-h-[${maxHeight}] h-[${maxHeight}] block px-6 pb-10`,
+                    "w-full block px-6 pb-10",
                     "overflow-auto",
                     wrapperProps?.className,
                 )}
+                style={{
+                    maxHeight,
+                    height: maxHeight,
+                    ...wrapperProps?.style,
+                }}
             >
                 {mdxSource ? (
                     <MDXRemote