My code:
```
CYCLE_OVERFLOW = Const(742500, Shape(width=22))
audgen_accum = Signal(22, reset=CYCLE_OVERFLOW) # Master clock
```
Amaranth:
```
    audgen_accum = Signal(22, reset=CYCLE_OVERFLOW) # Master clock
                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
...
TypeError: Reset value must be a constant-castable expression, not (const 22'd742500)
```
Why is this wrong? Why is a Const not a constant-castable expression?