It sounds like you are in that place that hovers between management and superior indidivual contributor work... rest assured you're not alone. I spent a long time in such a position before I seemed to become a permanent manager.
Realize that in many technical venues there's a fuzzy line like this. Early in technical work, many technical lead/manager types end up spending quite a bit of time managing the work but not the people. At this stage, the potential manager has a great deal of technical know-how and not a great deal of people know-how - so organizations will frequently let the person manage the tasks and the work, and do some, but not all, of the people-management. At this phase, you may do performance reviews or you may not. You may get asked for feedback... or not... it has a lot to with the organization and what both the informal and formal norms are for this.
Feedback giving is a real trick, and it can be explosive. It's not unusual for a fairly green manager to get left out of the loop a bit. I could wish it would be otherwise, because the only way to get good at feedback giving is practice - but it's not unusual for "the new guy" to not get solicited for information.
Some thoughts on your questions:
Was it my duty to know the management side of the process and write
something up?
If you were not asked, it was not your duty. There is often a line between "people who manage work getting done" and "people who manage people". I strongly suspect you are still in less people-centric side of management.
Realize that you may have been asked informally - if you had a debrief at the end of your project, it's very likely that commentary from such a debrief was factored in. It's not unusual for the responsibility for getting insights to fall on the manager to has to give the person their performance feedback.
Should I write up something now about each employee anyway and provide
it to upper management as supplementary material?
If you want to go the extra mile, figure out who the feedback-giving manager is and give them a quick, informal hello and ask if they want your feedback. I'd recommend this over giving any sort of long, formal writeup, as it may be WAY more than they want.
Realize that in a busy organization, corporate may have booked off as little as 1-2 hours of prep time per employee for their management to have collected, prepared and presented this feedback. So you writing a separate, long formal piece of feedback may be a LOT of information that they simply don't have time to make use of.
Easier is a quick phone call or drop-by hello where you can ask "hey, do you need anything?" and get a sense of what they want.
Should I be "reading between the lines" about my own future with this
employer?
NO.
Quite frankly, this isn't enough information to make any sort of a guess on, long term. If you want to know what your prospects for management are in this organization - ask. Don't try to read between the lines. Chances are good that you have some weak spots in your personal style that could use strengthening -- we all do! Get the feedback on the weak spots, mention your interest, ask about opportunities. That conversation will tell you 20 times more about your prospects in your job than guessing at something like this.