Large values in registers display incorrectly

Describe the bug Large values in registers are not displayed correctly. The loss of precision is reminiscent of that of JS floating point.

To Reproduce Steps to reproduce the behavior:

1. Create a binary that stores a large value in a register, like with or $0xffffffffffffffff, %rax
2. Load the binary in gdbgui and run starti
3. Step past the instruction

Expected behavior The value in rax should be displayed as 0xffffffffffffffff and 18446744073709551615.

Actual behaviour

Please complete the following information:

• OS: Linux 6.18.25, NixOS 25.11
• gdbgui version (gdbgui -v): 0.15.3.0
• gdb version (gdb -v): 16.3
• browser [e.g. chrome, safari]: LibreWolf 150.0-1
• python packages (pip freeze): (Nix unpins the versions in requirements.txt before building)

bidict==0.23.1
blinker==1.9.0
Brotli==1.2.0
click==8.2.1
dnspython==2.8.0
eventlet==0.40.0
Flask==3.1.2
Flask-Compress==1.17
Flask-SocketIO==5.5.1
greenlet==3.2.3
h11==0.16.0
itsdangerous==2.2.0
Jinja2==3.1.6
MarkupSafe==3.0.3
pygdbmi==0.11.0.0
Pygments==2.19.2
python-engineio==4.12.3
python-socketio==5.14.3
simple-websocket==1.1.0
six==1.17.0
Werkzeug==3.1.4
wsproto==1.2.0
zstandard==0.23.0

Additional context

18446744073709551615 + '' evaluates to '18446744073709552000' in JS.