Change Command History shortcut from ⌘H to ⇧⌘H

⌘H is reserved by macOS for "Hide Application" and pre-empts app-level
menu bindings before they ever fire, so the Command History shortcut
never actually worked. Moved to ⇧⌘H and updated all references (in-app
help, macOS Help Book, README).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

oAI/Resources/oAI.help/Contents/Resources/en.lproj/index.html

@@ -1535,7 +1535,7 @@ Whenever the user asks you to translate something, translate it to Norwegian Bok
                     <dt><kbd>⌘L</kbd></dt>
                     <dd>Browse Conversations</dd>
 
-                    <dt><kbd>⌘H</kbd></dt>
+                    <dt><kbd>⇧⌘H</kbd></dt>
                     <dd>Command History</dd>
 
                     <dt><kbd>⌘M</kbd></dt>