fix: add missing color definitions to example route

The example route was also missing generatePlaceValueColors() calls,
causing "unknown variable: color-ones" errors when rendering subtraction
examples. Added color definitions to both addition and subtraction templates.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

apps/web/src/app/api/create/worksheets/addition/example/route.ts

@@ -19,6 +19,7 @@ import {
   generateProblemStackFunction,
   generateSubtractionProblemStackFunction,
   generateTypstHelpers,
+  generatePlaceValueColors,
 } from '@/app/create/worksheets/addition/typstHelpers'
 
 export const dynamic = 'force-dynamic'
@@ -90,6 +91,8 @@ function generateExampleTypst(config: ExampleRequest): string {
 #let show-ten-frames = ${showTenFrames ? 'true' : 'false'}
 #let show-ten-frames-for-all = ${showTenFramesForAll ? 'true' : 'false'}
 
+${generatePlaceValueColors()}
+
 ${generateTypstHelpers(cellSize)}
 
 ${generateProblemStackFunction(cellSize, 3)}
@@ -132,6 +135,8 @@ ${generateProblemStackFunction(cellSize, 3)}
 #let show-borrow-notation = ${showBorrowNotation ? 'true' : 'false'}
 #let show-borrowing-hints = ${showBorrowingHints ? 'true' : 'false'}
 
+${generatePlaceValueColors()}
+
 ${generateTypstHelpers(cellSize)}
 
 ${generateSubtractionProblemStackFunction(cellSize, 3)}