skill-stocktake scan.sh misses symlinked skill directories

skills/skill-stocktake/scripts/scan.sh uses plain find "$dir" -name "*.md" -type f. Plain find doesn't descend into symlinked subdirectories, so any skill installed as a symlink (common: package-manager installs, app-bundled skills, cross-tool shared skills) is silently dropped from the inventory.

Repro: 4 skills under ~/.claude/skills, 3 of them symlinks. scan.sh reported only 1.

Fix: use find -L "$dir" -name "*.md" -type f.