fix(preview): relative path links take m4v and ogv like rooted ones (#604/#606 integration)

#606 added m4v and ogv to the rooted file-path link pattern for the new video
uploads; #604's relative path pattern copies that extension list, and its
test pins the two equal. The relative pattern now carries them too, so a
relative `clip.m4v` links like `/home/u/clip.m4v`.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

src/web/public/constants.js

@@ -2095,7 +2095,7 @@ function previewsInFileViewer(filePath) {
  * {@link findFilePathLinks}.
  */
 const RELATIVE_FILE_PATH_LINK_PATTERN =
-  /(^|[\s"'`(\[{<>=,])((?![^\s"'`<>|;&()[\]{}=,\n\x00-\x1f]*:\/\/)(?:~\/|[^\s"'`<>|;&()[\]{}=,\/~\n\x00-\x1f])[^\s"'`<>|;&()[\]{}=,\n\x00-\x1f]*\.(?:log|txt|json|md|ya?ml|csv|xml|sh|py|tsx|ts|jsx|js|mjs|cjs|css|html|toml|ini|sql|png|jpe?g|gif|webp|avif|bmp|ico|svg|pdf|docx|pptx|xlsx|mp4|webm|mov|mp3|wav))\b/g;
+  /(^|[\s"'`(\[{<>=,])((?![^\s"'`<>|;&()[\]{}=,\n\x00-\x1f]*:\/\/)(?:~\/|[^\s"'`<>|;&()[\]{}=,\/~\n\x00-\x1f])[^\s"'`<>|;&()[\]{}=,\n\x00-\x1f]*\.(?:log|txt|json|md|ya?ml|csv|xml|sh|py|tsx|ts|jsx|js|mjs|cjs|css|html|toml|ini|sql|png|jpe?g|gif|webp|avif|bmp|ico|svg|pdf|docx|pptx|xlsx|mp4|webm|mov|m4v|ogv|mp3|wav))\b/g;
 
 /** The `(?:log|txt|…)` extension group, read off the rooted pattern so it cannot drift. */
 const FILE_LINK_EXTENSION_GROUP = /\\\.(\(\?:[^()]*\))\)\\b$/.exec(FILE_PATH_LINK_PATTERN.source)[1];