docs(design): remove SVG, use PNG logo only

SVG icon is no longer in use. public/logo.png (1024x1024 RGBA) is
the single logo asset. DESIGN.md updated accordingly: SVG snippet
removed, wordmark pattern and <head> references updated to PNG.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

node_modules/lines-and-columns/build/index.d.ts

@@ -0,0 +1,13 @@
+export declare type SourceLocation = {
+    line: number;
+    column: number;
+};
+export declare class LinesAndColumns {
+    private string;
+    private offsets;
+    constructor(string: string);
+    locationForIndex(index: number): SourceLocation | null;
+    indexForLocation(location: SourceLocation): number | null;
+    private lengthOfLine;
+}
+export default LinesAndColumns;