misconstructed plant causes dkpy to hang indefinitely using 100% cpu for hours with no progress

# Expected Behavior
dkpy should detect malformed plants if practical, or crash with helpful messages, or provide some way to see (lack of) progress. (I will open a separate issue for the latter). ctrl+c should kill the program.

# Actual Behavior
A plant was created missing one of the middle outputs. This could have been identified by a mismatch between the plant output count and (ny+blocksize). Instead it caused dkpy to hang indefinitely using 100% cpu for hours with no progress. it did not respond to ctrl+c. had to kill with `killall -9 python`

# Steps to Reproduce the Problem
Let me know if you want the code with the bad plant. it's ~200 lines of code. I haven't tried to create a minimal example, but I can work on that if you prefer that over seeing the original code.

# Specifications

- Package version: 0.1.8
- Python version: Python 3.13.3
- Platform: arch