[Tingliangstu]

Change

Support explicit disconnected paths with q_path_name = GXU|KGL (quotes optional) and num_qpaths = 4. This computes Gamma-X-U and K-Gamma-L, without generating the unintended U-K segment. | specifies connectivity, not degeneracy or symmetry equivalence.

• Preserve each sampled segment's column range in .Q_distances_and_labels and render segments independently for total and partial SED. Existing files without this metadata remain readable.

• Use requested Cartesian path lengths for distances and labels; report unsampled endpoints and retain empty segments as gaps rather than silently converting them into breaks.

• Update the Si input, its path instructions, the input template, and manual. Recalculation is required after changing path connectivity.

• Print the full path and explicit terminal break notices, e.g. Path break : U|K (no connecting segment), between path groups.

Benefit

The Si path definition now stays the same for 20, 40, and 41 repeats. Previously, U-K disappeared only when no commensurate points existed on that segment; 40 repeats produced an unintended connecting segment. Saved topology also prevents plotting from interpolating between distinct endpoints at a break.

Related to #36. This addresses the identified path-definition issue; it does not claim a rerun of the original reported MD trajectory.

Validation

• WSL existing pysed environment: full suite 123 passed, 344 subtests passed, including CuPy/GPU tests.

• Windows focused parser/path/output/plot/CLI suite: 54 passed.

• Windows full suite: 120 passed, 1 skipped, 2 failed. Both failures reproduce on unchanged base 1e99ed9: text-file CRLF byte-offset assertion and persistent-worker native thread-limit assertion. No unrelated fixes included.

• Strict Sphinx HTML build (-W --keep-going): passed.

• Visually inspected saved/reloaded synthetic spectra for 20, 40, and 41 repeats. Deliberately unequal peaks on either side of U|K stay disconnected; missing commensurate endpoints remain unfilled. Regression tests also cover partial SED, multiple breaks, malformed inputs, empty and single-point segments, and historical output loading.

• Terminal-output follow-up: 15 path tests passed; directly checked the break position, multiple breaks, continuous paths, and quiet mode.