Random observations and questions. That crack did happen 1" from the highest force point on the bike, the fork crown at the headset. All of the bending moment on the fork, both routine from rider weight and road vibration to potholes to bunny hops to car doors ... happen there and in equal and opposite direction by the head tube, assisted by the down tube. That tube juncture is the most critical to keeping the bike and rider off the road.
I have never liked the idea of welded steel bikes. I am much more comfortable with the idea of lugs, especially for production bikes made in large numbers. Welds are hot. That heat extends quite far from the weld itself. How much depends on the mass of the parts to be welded and to welder skill. Same is true of brazing but the brazing temperatures are much lower. I have often wondered how long welded frames last. I didn't start seeing high quality welded frames until the late '90s. Just now, those frames are starting to get to what I call the "mature years" of good steel frames, 50k miles.
This bike has shown something I do not want to see on my bikes. First crack in a critical place. I've lived through (barely) a bike breaking that one inch away. I've also retired bikes with broken BBs, chainstays (2 or 3 times), had repaired seat stays, chainstays and BBs. My Peugeot UO-8 failing at the chainstay at 22,000 miles and dozens of crashes - a good failure. No one gets hurt. Likewise BB shells, seatstays. But that fork at the crown? My nightmare. My strong opinion is that bike should be so built that something in the back of the bike always fails before any frame part between the front hub and the handlebars and including the front 6" of the top and down tubes. (Excepting in crashes big enough to obviously bend or break the frame.)
Bikes, if ridden long enough, break. They all do. The manufacturer of the bike can do things to improve the odds that the failures happen at "safer" places. So, sounds backwards, I see it as good practice to make the BB details or chainstay or seatstay details a little less bulletproof so they don't do go forever. I am one fully guilty of riding bikes into the ground. That Peugeot. A half dozen winters on salt roads, two car doors (retired on the 2nd) ... My Miyata 610, a very well built frame - retired on its 3rd hard, fork ending crash. Now I am in my later years. I now longer make frames old muscling big gears up hill. But I still want a fork, headtube and headtube, top and down tube lug attachments steel) I trust completely (or ti welds there by a builder I trust) so I never have to go through that nightmare again.
Thulsadoom, you caught this in time. It's steel so the crack developed slowly enough to be noticed. (One reason I love steel.) All good! A happy ending for a frame that has served you well. Now, if you really liked that frame, consider taking it to a custom builder and asking him to "make me another, only tweak this, put a braze-on there and I really like those lugs!" (My Mooney was built to be the non-racing bike to replace the Fuji Pro I loved but was race only. Now 3000 miles behind your Trek, 2nd paint but maybe midway through its life (if someone takes it on after I go, it's going to outlive me by many years).