That crap camera also doesn't want to focus up that close. Hence the really fuzzy focus. If it has a "flower" or macro setting try that.
Looking at the fuzzy picture it looks like any front sight will have to be quite tall. To check this lay a straight edge along the top strap and then plan on the front sight being around another 1/32 taller than that. I think you'll find that you've got pleanty of room for a base and blade setup and that a simple bead would not be suitable.
How's your skill at wielding a metal file? With a lump of steel and a couple of files you should be able to cobble up a base and blade to let you put a proper front sight on that puppy.
And the nice thing about a sight with a proper base is that there's enough surface area to allow you to soft solder the base to the barrel. On the other hand if you use JUST a blade it'll be tall enough that it pretty much needs to be silver soldered using the high heat stuff. The soft solder won't lift the nickel where using a torch and bringing up the end of the barrel to near glowing most certainly will lift what nickel remains.
I know it's not a big deal but if you can keep the finish as intact as practical it would make the cleanup work after mounting the front sight that much less work.
In my mind I'm thinking of a sight made from 1/4 stock where the sides would be filed using a half round file to produce a blade section that looks much like a hollow ground gunsmith's screwdriver tip. Then the base would be filed using a round file that is a little smaller in diameter than the barrel. Once the section is shaped like this then from the side it would be cut down to produce a nice smooth half teardrop shape so that it's a nice smooth non catching draw. Work with the shape until it all looks nicely square and sits on the barrel with the blade sides alingned nicely with the center of the bore. Then clean the area free from nickel plating under where the base will go. Smear it with a bit of soldering flux paste then firmly wire it on with some small section steel tie wire and go shoot it. Come to think of it you will want to leave the side shape a bit more square for this step and file the nice tear drop shape later. This first go round you're just looking for it to center for windage so don't worry about the height or if you need to angle the gun to allow the blade to be more visible for aiming. With it set scribe a witness line so you can reset it or very carefully transport it home and soft solder it to the barrel. Once mounted now you can worry about cutting the height down to finish the sighting in process.
If you're missing some of what I'm describing I could do up a sketch of how I'm thinking that the blade would be shaped and wired in place for soldering.
If you go this route your costs may ramp up by the cost of two files to do the shaping assuming you can find a small scrap of metal for free...