Removes from git index: node_modules.bak/, .lintdeps/, .scannerwork/,
.DS_Store, dist/, etc. — regenerable build/scan outputs that should
never be tracked. Updates .gitignore with the canonical pattern set.
Audit dimension `tracked-artifacts` (core/go commit 62aac07) flagged
2 entries. Same root-cause class as Mantis #1333 (gui
ui/node_modules.bak/) — applying the structural fix ecosystem-wide.
Co-Authored-By: Cladius Maximus <cladius@lethean.io>