math: make tracker public (read-only for visitors)

src/lib/math.ts

@@ -6,7 +6,7 @@
  * list). false: a public, read-only page for everyone else (notes stay owner-only, edits
  * are always owner-only). Flip this one constant; owner.ts and projects.ts read it.
  */
-export const MATH_PRIVATE = true;
+export const MATH_PRIVATE = false;
 
 export const MATH_STATUSES = ['not_started', 'reading', 'exercises', 'done', 'skipped'] as const;
 export type MathStatus = (typeof MATH_STATUSES)[number];