Casting a line into Guppy's depths

Added a dedicated error diagnostic for using Guppy functions or types inside comptime() expressions, replacing raw Python tracebacks with a message that explains the problem and how to fix it.

Fixed a file system bug where Guppy looked for WASM modules relative to the current working directory instead of the source file's location, breaking Jupyter notebook workflows.

Improved error messages when a quantum struct member causes a linearity violation — errors now point at the specific member rather than internal data, making bugs easier to diagnose.