fix some minors issues

[cxzhong]

1. add pytest function
2. upgrade uv lock
3. fix a minor warnings
4. drop 3.11

[cxzhong]

Without <object>, the arithmetic stays at the C level where integers are fixed-width (64-bit), causing overflow/undefined behavior. With <object>, the values are promoted to Python's arbitrary-precision integers, correctly reconstructing the full 128-bit value from the lo and hi halves.

[cxzhong]

CC: @dimpase