Vectors larger than 64 bits are not supported

[urish]

For example, taking the default "Stripes" demo and changing the bit width of counter in line 40:

-  reg [9:0] counter;
+  reg [64:0] counter; 

Causes the simulator to fail with:

WI: cannot load 16 bytes (> 64 bits not supported)

This is thrown from https://github.com/TinyTapeout/vga-playground/blob/main/src/sim/hdlwasm.ts - there are a few more places where operations on vectors wider than 64 bits are not supported (just search for "64 bits" to find the relevant error messages).