M3's optical size axis redraws a symbol so its strokes look equally heavy at
every size; drawing the 24 cut at 20px thins them by about a sixth (styles.md
§ Icons). `optical` picks the cut — 24 by default, 20 for an icon drawn at 20px
or smaller — and combines with `filled`; anything else falls back to 24, so no
caller can land on a folder that does not exist. SvgFile::symbol() takes the
size as a fourth argument and resolves the `-20` folders; the catalogue is the
same in both cuts, so symbolNames() and DesignGuard's icon-name check are
unchanged. The callers that size their own icons pass it in a later step.
Plan step 10; finding C16.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Qwx5USif3wFFmxtHg5U1g9
