After rebounding some 65% from its April lows, bitcoin seems to have hit a ceiling. The world's biggest cryptocurrency has mostly flatlined over the last three months, a period in which it has reached its record high around $124,000.There may be no obvious reason or catalyst. The risks are well-known by now - stretched valuations, positioning, concentration, and faith in AI's productivity-enhancing powers. And the Fed is cutting rates now, so that's more fuel for the rally, right? Perhaps. Or perhaps it mar ...