fix(composer): no LaTeX conversion inside a typed markdown fence or backtick span (#184 O3)

In markdown mode each paragraph line is serialised before parseBlockMD
joins them, so $x$ inside a ``` fence became data-mx-maths markup
inside the resulting <pre><code> (rendered as math in a code block).
Track fence state across lines and skip math for fenced lines and for
backtick code spans. Unit tests added; verified in the browser.

Also: scripts/dev-homeserver.sh enables MSC4140 delayed events so
scheduled messages work locally.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PPmy3tPq869XDW4njjVaKA

src/app/components/editor/output.ts

@@ -36,6 +36,18 @@ const textToCustomHtml = (node: Text, opts: OutputOptions): string => {
   // applied inside inline code. Non-math text recurses with allowMath off so it
   // still gets the normal marks + inline-markdown treatment.
   if (opts.allowMath && !node.code) {
+    // Markdown inline code spans (`…`) are literal too: apply math only to the
+    // text between them (Gitea #184 O3 — `$x$` inside backticks stayed math).
+    if (opts.allowInlineMarkdown && /`[^`]*`/.test(node.text)) {
+      return node.text
+        .split(/(`+[^`]*`+)/)
+        .map((part) =>
+          part.startsWith('`')
+            ? textToCustomHtml({ ...node, text: part }, { ...opts, allowMath: false })
+            : textToCustomHtml({ ...node, text: part }, opts),
+        )
+        .join('');
+    }
     const segments = splitMathSegments(node.text);
     if (segments.some((seg) => seg.type !== 'text')) {
       return segments
@@ -128,12 +140,20 @@ export const toMatrixCustomHTML = (
   opts: OutputOptions,
 ): string => {
   let markdownLines = '';
+  // Inside a markdown ``` fence every line is literal: no `$…$` math conversion
+  // (the fence is only recognised by parseBlockMD after the lines are joined,
+  // which is too late — Gitea #184 O3).
+  let inFence = false;
   const parseNode = (n: Descendant, index: number, targetNodes: Descendant[]) => {
     if (opts.allowBlockMarkdown && 'type' in n && n.type === BlockType.Paragraph) {
+      const isFenceLine = /^\s*```/.test(toPlainText(n, false));
+      const literal = inFence || isFenceLine;
+      if (isFenceLine) inFence = !inFence;
       const line = toMatrixCustomHTML(n, {
         ...opts,
         allowInlineMarkdown: false,
         allowBlockMarkdown: false,
+        allowMath: opts.allowMath && !literal,
       })
         .replace(/<br\/>$/, '\n')
         .replace(/^(\\*)&gt;/, '$1>');