Avoid monitor JavaScript redeclaration errors

[godmafiaze]

This PR updates top-level declarations in js/monitor.js from let / const to var.

The Monitor page can reload content through AJAX. When monitor.js is executed more than once, top-level let / const declarations can throw JavaScript redeclaration errors, such as:

Uncaught SyntaxError: Identifier 'refreshMSeconds' has already been declared

This can prevent Monitor dropdowns and filter controls from applying changes correctly after an AJAX reload.

This change keeps block-scoped declarations inside functions unchanged and only adjusts the top-level declarations that may be executed more than once.

Fixes #220

Tested:

• Verified the Monitor page no longer throws the refreshMSeconds redeclaration error
• Verified Monitor dropdown/filter controls continue working after AJAX reload
• Verified git diff --check returns no whitespace errors

[TheWitness]

This bit is interesting. I'm pretty sure I know how it happened. Good job!

[TheWitness]

@somethingwithproof, I think the AI did this one. It's a global either in layout.js or global_session.php. Pretty sure in global_session.php.