Added 80 column fix from Sorcha code

[Little-Ryugu]

Added _split_kernel_path_str and its unit test from Sorcha to avoid 80 column bug

Fixes #433 .

Describe your changes.

Review Checklist for Source Code Changes

• Does pip install still work?
• Have you written a unit test for any new functions?
• Do all the units tests run successfully?
• Does Layup run successfully on a test set of input files/databases?
• Have you used black on the files you have updated to confirm python programming style guide enforcement?

[matthewholman]

Nice work, Ryan — tested it end-to-end and it fixes the bug. A long (~165-char) cache path reproduced the TYPEMISMATCH on main. Confirmed your change lets a kernel actually load through the generated meta_kernel.txt. The comma in +',\n' is the real fix.

One non-blocking note: the unit test checks the split string but never calls furnsh, so it wouldn't catch a break in the actual SPICE load. Here's a short integration test that guards the real behavior — builds a meta_kernel under a deliberately deep path and loads a kernel through it:

import os
import spiceypy
from layup.utilities.bootstrap_utilties.create_meta_kernel import _split_kernel_path_str


def test_meta_kernel_loads_under_long_path(tmp_path):
    # A cache path long enough to trip the SPICE 80-char string limit.
    deep = tmp_path
    while len(str(deep)) < 160:
        deep = deep / "12345678"
    deep.mkdir(parents=True, exist_ok=True)

    # A tiny kernel we can check actually loaded.
    (deep / "tiny.tls").write_text(
        "\\begindata\nDELTET/DELTA_T_A = 99.5\n\\begintext\n"
    )

    mk = deep / "meta_kernel.txt"
    mk.write_text(
        "\\begindata\n\n"
        f"PATH_VALUES = ('{_split_kernel_path_str(str(deep))}')\n\n"
        "PATH_SYMBOLS = ('A')\n\n"
        "KERNELS_TO_LOAD = ( '$A/tiny.tls' )\n\n"
        "\\begintext\n"
    )

    spiceypy.kclear()
    try:
        spiceypy.furnsh(str(mk))                     # would raise TYPEMISMATCH before the fix
        assert spiceypy.gdpool("DELTET/DELTA_T_A", 0, 1)[0] == 99.5
    finally:
        spiceypy.kclear()

(Also, docstring says default 79 but it's split=77.) Approve after that — thanks for the quick turnaround!

[Little-Ryugu]

No worries. I fixed the docdtring for sorcha but forgot layup oops. Thats a very good point with the unit test, it caused us to miss the bug in Sorcha. I'll add that test to both repos too thank you!!

[matthewholman]

Looks good!