fix(player): a description link keeps its sentence's punctuation and its own parentheses

The trailing .,;:!?)] was trimmed off the href and dropped from the text too, and a URL ending in a
balanced ")" (a Wikipedia article) was cut short. The trim keeps a closing paren that has its
opener, and the trimmed tail is put back after the link.

frontend/src/components/descriptionLinks.dom.test.tsx

@@ -0,0 +1,43 @@
+// @vitest-environment jsdom
+//
+// E28 review C6: a link at the end of a sentence lost the punctuation after it — the trailing
+// `.,;:!?)]` was trimmed off the href and then dropped from the text too — and a URL whose own path
+// ends in a balanced ")" (a Wikipedia article) was cut short and broken.
+import { afterEach, describe, expect, it, vi } from "vitest";
+import { cleanup, render } from "@testing-library/react";
+import type { TFunction } from "i18next";
+
+import { renderDescription } from "./descriptionLinks";
+
+afterEach(cleanup);
+
+function shown(text: string) {
+  const { container } = render(
+    <div>
+      {renderDescription(text, {
+        currentId: "x",
+        onSeek: vi.fn(),
+        onLoadVideo: vi.fn(),
+        t: ((k: string) => k) as unknown as TFunction,
+      })}
+    </div>,
+  );
+  return {
+    text: container.textContent,
+    hrefs: [...container.querySelectorAll("a")].map((a) => a.getAttribute("href")),
+  };
+}
+
+describe("a link in a description", () => {
+  it("keeps the punctuation after it in the text, out of the link", () => {
+    const r = shown("See https://example.com/page. And (https://example.org/x), too!");
+    expect(r.text).toBe("See https://example.com/page. And (https://example.org/x), too!");
+    expect(r.hrefs).toEqual(["https://example.com/page", "https://example.org/x"]);
+  });
+
+  it("keeps a balanced parenthesis that belongs to the address", () => {
+    const r = shown("Read https://en.wikipedia.org/wiki/Mercury_(planet).");
+    expect(r.hrefs).toEqual(["https://en.wikipedia.org/wiki/Mercury_(planet)"]);
+    expect(r.text).toBe("Read https://en.wikipedia.org/wiki/Mercury_(planet).");
+  });
+});

frontend/src/components/descriptionLinks.tsx

@@ -53,6 +53,22 @@ function parseYouTube(url: string): { id: string; start: number | null } | null
   return { id, start: parseStart(u.searchParams.get("t") || u.searchParams.get("start")) };
 }
 
+/** The address inside a matched URL: sentence punctuation after it is not part of it, but a ")" that
+ *  closes a "(" of its own is (a Wikipedia article's "Mercury_(planet)"). */
+function trimUrl(raw: string): string {
+  let end = raw.length;
+  for (;;) {
+    const c = raw[end - 1];
+    if (c && ".,;:!?]".includes(c)) end--;
+    else if (c === ")") {
+      const body = raw.slice(0, end);
+      if (body.split(")").length > body.split("(").length) end--;
+      else break;
+    } else break;
+  }
+  return raw.slice(0, end);
+}
+
 export function renderDescription(
   text: string,
   opts: {
@@ -74,7 +90,9 @@ export function renderDescription(
     .trim();
   for (const chunk of clean.split(URL_RE)) {
     if (/^https?:\/\//.test(chunk)) {
-      const href = chunk.replace(/[.,;:!?)\]]+$/, "");
+      const href = trimUrl(chunk);
+      // What was trimmed is the sentence's, not the link's: it stays in the text, after the link.
+      const tail = chunk.slice(href.length);
       const yt = parseYouTube(href);
       if (yt) {
         const sameVideo = yt.id === opts.currentId;
@@ -98,6 +116,7 @@ export function renderDescription(
           </a>,
         );
       }
+      if (tail) out.push(<span key={key++}>{tail}</span>);
       continue;
     }
     // Plain text: pull out emails, hashtags and bare timestamps.