CMD + F Keyword lookup feature needed

CMD + F should enable a simple regular expression lookup to see if anything in the content matches.

So a user can essentially hit CMD + F -> small dialog of popup type or integrated dialog box type appears, in order to write what you are looking for -> hit search -> the relevant text is highlighted in yellow.

Accommodate so that "Replace" and "find replace" functions can be latter added.

No files, tests, or entry points are identified in the issue. Start by locating the Mac app's command handling and content-search UI, then determine how CMD+F, regular-expression matching, yellow highlighting, and a future Replace workflow should fit together. Done means a search dialog opens, matching content is highlighted, and the design leaves room for Replace and find-and-replace.

Written by the indexing model from the issue text.