Finally got around to a manual test of WikidProject and... it works! My god, it actually works!
Well the tests in place should have instilled confidence that it would -- and they did -- but there's still always that little kick in the gut when you actually see a new page appear in the filesystem.
Far from perfect... click on a Nonexistent-Page link and it takes you to the view of the new page, and then you can edit the page and have the new content persist. In a better version I'd prefer the original link to Nonexistent-Page take me directly to the Edit page. Baby steps, baby!
I feel like the skeleton is now actually walking, and that feels good.
The question is, "What next?" From the above, I feel an urgency about that Edit-link issue, but... is this the most important thing I should be working on? Time to resurface and think about strategic goals.