to_obsidian / to_canvas / to_wiki keyed filename dedup on the exact-case name,
so two labels differing only by case (e.g. `References` vs `references`) counted
as non-colliding and the second write clobbered the first on case-insensitive
filesystems (macOS/APFS, Windows/NTFS) — silently, no suffix, no warning.
Dedup now folds case (keyed on the lowercased name) while emitting the
original-case filename, so any pair that would collide on disk gets a numeric
suffix. The obsidian/canvas dedup is one shared helper (`_dedup_node_filenames`)
so they can't drift; wiki's slug dedup gets the matching fix; the `_COMMUNITY_*`
overview notes (which had no dedup at all) are covered; and a generated `base_1`
is re-checked so it can't overwrite a node literally labelled `base_1`.
Ported from PR #1457 by @TPAteeq onto current v8. Verified with a rigorous
edge-case battery (case-only collision, base_1 literal re-check -> base_1_1,
community-label case fold, determinism) plus the PR's tests; full suite 2404
passed, ruff + skillgen clean.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Mohammed Ateeq
5d63aad596