Try-catch around localstorage access

There are ways a localstorage read/write can fail and throw something like `Uncaught DOMException: The quota has been exceeded.`. This can be because the browser doesn't support it (i.e. Safari in private mode) or localstorage has reached its global limit (as reported by @sammyjava). We should wrap them in a try-catch and dispatch a :messages/add telling the user, "Failed to read/write to localstorage. Please use a different browser or clear your browser data as it may be full."

Search the ClojureScript codebase for localStorage reads and writes, then inspect the existing :messages/add dispatch path. Handle failures for both operations with the specified user-facing message, and verify that normal storage behavior remains unchanged.

Written by the indexing model from the issue text.