Hire people to stand at the entrance with a hand-counter (one for entry, one for exit). Have them jot down the count every half hour. Cheap, easy, foolproof.
Next time, first look how well the competition is doing before coding up the same thing.
As for why vertical tabs are not popular: for me it's because it is annoyingly similar, and right next to, the navigation pane of the website I'm looking at.
This leads to clicks on the wrong "navigation pane".
Show how it would work in practice, show how it is better than normal Jira search. Show why I should use your project instead of the many, many others?
I don't use it. Somehow I'm constantly checking how much time remains. Can't get into the flow. And if I do get into any kind of flow state, the last thing I want is to get interrupted by a timer.
I think it might work great for physical work. Remembering to stretch or take a break. But, for me, not for any type of brainy work.
This mandatory harvesting of personal information is atrocious. Inevitably these personal email addresses get stolen, leaked or just sold to everyone that wants it. The user get a deluge of spam and/or targeted scams. Just let the user enter a one-time email if they wish. There is a reason they don't want to give out their 'real' address.
You're part of the problem of the modern internet.
I'd suggest connecting all your gear with the appropriate cables. Any left over cables can go to the recycling center. You're never going to need them.
For work I use a calendar (Outlook) as a todo list. A task gets added to a date and time in the future so I know I can't forget it. When the day comes, I either do the thing, or I postpone it to a later date. For clarity: I don't use the taskplanner, but add tasks as appointments in the calendar.
This solves, for me, the problem of picking the 'right' thing to do from my list. I just do the things for that day. Be flexible, when you have extra time you can pull things closer, when it's balls to the wall, just shift some tasks to a later date.
I've been doing this for about 25 years, it works for me, might work for others too.
edit: I don't do notes, as such. Never felt the need to write something down that I won't ever look at again anyway.
Knuth can be a bit of an acquired taste. In my opinion it isn't very useful to read if you don't fully commit to do the exercises. That will take time and a lot of it! I suggest you postpone this one. You have enough to study already.
I think that argument only holds when the customer is informed about those specific tradeoffs. The customer will choose the cheap bulbs because they can't be sure the expensive ones are better quality. They often aren't.
Buyers want cheap bulbs, they don't want crap bulbs. If that means $1.25/unit is impossible, so be it.
To ensure employment either be a specialist (so you can do something others can't), or choose an older technology that used to be popular but isn't now. Most developers will have moved on, and now you can do the thing others don't want to learn anymore.
Is it glamorous? Does it pay top dollar? No and no, but it is a very secure income.
I'm not suggesting you start doing COBOL. Think more along the line of Java, which has an enormous installed base and nobody wants to have anything to do with it if they can help it. That's an opportunity for you to step in.
Same thing for Perl, there's a lot of existing code that needs maintenance. I'm sure you can think of a few other languages and technologies that fit this category.