Widens _SLUG_SUFFIX_RESERVE/_DEDUP_SUFFIX_RESERVE from 4 to 5 so a four-digit
collision suffix (_1000..) can't push a truncated stem past MAX_PATH; the
suffix is technically unbounded but 5 chars covers ~10k identical stems. Adds
an end-to-end test that CJK labels at a tight budget stay within the window,
keep their non-ASCII characters, and produce links that resolve on disk.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Adds paths.stem_filename_budget(output_dir, *, reserve, limit=200) and threads
it through the Obsidian and wiki exporters so a filename stem is budgeted
against the whole Windows MAX_PATH window (drive + dirs + name + NUL), not
just the per-component 200-char NAME_MAX cap. On POSIX the helper returns the
limit unchanged, so existing vaults stay byte-identical; on Windows a long
output directory no longer pushes the total path over MAX_PATH and aborts the
export mid-write.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
