Shortcut labels were rebuilt from scratch in the render body of every
component that shows one, which kept parseKeybinding running ~120x/sec
in a fully idle app.
- Cache the label layer per overrides object (WeakMap), so a keybinding
edit hands out a new object and therefore a fresh cache.
- Memoize parseKeybinding behind a bounded cache; binding strings come
from a fixed definition set plus user overrides.
- Hoist the per-call token/label object literals in normalizeKeyToken
and formatKeyToken to module constants.
Renames seven -helpers modules for the concept their functions operate on, and
splits three that were genuine grab-bags -- each had a clean cleavage along its
importers, which is the signal AGENTS.md describes for a file holding more than
one responsibility.
Leaves keybindings/definitions-core-1..4 alone: definitions.ts spreads them in
order, so their concatenation order is the command palette order and regrouping
them thematically would be a user-visible change. Records that reasoning in a
comment so it is not re-litigated.
Neil