lat check: Windows path separator breaks bare-name section lookup in index files

[cappellaadrian]

Summary

On Windows, lat check produces false-positive broken link errors for every short-form [[<name>]] wikilink that appears in a directory-index file (e.g. the auto-generated codigo/codigo.md or top-level lat.md). The same project on macOS/Linux validates clean.

Repro (Windows 11, Node 24.11.1, npm 11.6.2, lat.md 0.11.0)

mkdir lat-windows-bug && cd lat-windows-bug
lat init
# Optionally add a sub-directory with multiple .md files:
mkdir codigo && cd codigo
echo "# A" > a.md
echo "# B" > b.md
echo "# Codigo`n[[a]] [[b]]" > codigo.md
cd ..
lat check

Expected: 0 errors.

Actual on Windows:

Scanned ... in ~400 ms
2 errors found
  codigo\codigo.md: [[a]] not found
  codigo\codigo.md: [[b]] not found

The fully-qualified links [[codigo\a]] and [[lat.md\codigo\a]] resolve correctly. Only the short bare-name form fails — even though lat's own lat init scaffold and the README examples both use the short form inside index files.

Root cause

dist/src/lattice.js:200 (in buildFileIndex()):

const baseName = s.file.split('/').pop();

Path values inside the section index are stored using the native OS separator. On Windows that's \, so 'codigo\codigo.md'.split('/').pop() returns 'codigo\codigo.md' (the whole path) rather than 'codigo.md'. The bare-name lookup table never gets populated, so the validator can't find any of the targets.

Suggested fix

- const baseName = s.file.split('/').pop();
+ const baseName = s.file.split(/[\/]/).pop();

Or equivalently use path.basename(s.file) for the same OS-neutral behavior.

Workaround until released

Use fully-qualified [[full/path#Section]] everywhere, never bare-name [[Section]]. Sacrifices the directory-listing convention the README documents but unblocks lat check.

Context

Found while migrating a structural engineering knowledge graph (8 directory-index files, 18 broken-link false positives, all caused by this one line). The rest of the lattice — wiki links, code annotations (// @lat:), lat section, lat refs, lat locate — works perfectly on Windows. Thanks for shipping this — it's a great tool.