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/(functions)/popver/grab-popover-styles.ts

@@ -14,6 +14,10 @@ export default function twuiGrabPopoverStyles({
 }: Params): React.CSSProperties {
     if (!targetElRef.current) return {};
     const rect = targetElRef.current.getBoundingClientRect();
+    // Absolute `right`/`bottom` resolve against the initial containing block,
+    // which excludes scrollbars (unlike window.innerWidth/innerHeight)
+    const viewportWidth = document.documentElement.clientWidth;
+    const viewportHeight = document.documentElement.clientHeight;
 
     const targetElCurrStyles = window.getComputedStyle(targetElRef.current);
 
@@ -31,7 +35,7 @@ export default function twuiGrabPopoverStyles({
     };
 
     const defaultTopStyleStyle: React.CSSProperties = {
-        bottom: window.innerHeight - (rect.top + window.scrollY) + 8,
+        bottom: viewportHeight - (rect.top + window.scrollY) + 8,
         left: rect.left + window.scrollX + rect.width / 2,
         transform: "translateX(-50%)",
     };
@@ -43,7 +47,7 @@ export default function twuiGrabPopoverStyles({
             popoverStyle,
             _.omit(defaultBottomStyle, ["transform"]),
             {
-                left: rect.left,
+                left: rect.left + window.scrollX,
             } as React.CSSProperties
         );
     } else if (position === "bottom-right") {
@@ -52,7 +56,7 @@ export default function twuiGrabPopoverStyles({
             _.omit(defaultBottomStyle, ["left", "transform"]),
             {
                 right:
-                    window.innerWidth -
+                    viewportWidth -
                     (rect.left + window.scrollX) -
                     rect.width -
                     targetElRightPadding,
@@ -66,8 +70,7 @@ export default function twuiGrabPopoverStyles({
         popoverStyle.transform = "translateY(-50%)";
     } else if (position === "left") {
         popoverStyle.top = rect.top + window.scrollY + rect.height / 2;
-        popoverStyle.right =
-            window.innerWidth - (rect.left + window.scrollX) + 8;
+        popoverStyle.right = viewportWidth - (rect.left + window.scrollX) + 8;
         popoverStyle.transform = "translateY(-50%)";
     }