fix(worksheets): align makeEasier fallback with spec priorities

Fix makeEasier fallback to match spec (line 866):
"makeEasier: Add support first (scaffolding), then reduce complexity (regrouping)"

Previous implementation tried regrouping first, which was backwards.

Pedagogical rationale: Give more help first while problems stay same
difficulty, then simplify problems once they have support structures
in place.

This creates intentionally different but pedagogically sound paths for
harder vs easier navigation.

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

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

apps/web/src/app/create/worksheets/addition/difficultyProfiles.ts

@@ -1041,22 +1041,20 @@ export function makeEasier(
     }
 
     // Fallback: If we couldn't move toward preset, try any valid easier move
+    // Per spec: makeEasier should add support (scaffolding) first, then reduce complexity (regrouping)
     if (!moved) {
-      // Try decreasing regrouping first
-      if (newRegroupingIdx > 0) {
+      // Try decreasing scaffolding (adding help) first
+      if (newScaffoldingIdx > 0 && isValidCombination(newRegroupingIdx, newScaffoldingIdx - 1)) {
+        newScaffoldingIdx--
+        moved = true
+      }
+      // Otherwise try decreasing regrouping (reducing complexity)
+      else if (newRegroupingIdx > 0) {
         const testRegroupingIdx = newRegroupingIdx - 1
         newRegroupingIdx = testRegroupingIdx
         newScaffoldingIdx = clampScaffoldingToValidRange(testRegroupingIdx, newScaffoldingIdx)
         moved = true
       }
-      // Otherwise try decreasing scaffolding (adding help)
-      else if (
-        newScaffoldingIdx > 0 &&
-        isValidCombination(newRegroupingIdx, newScaffoldingIdx - 1)
-      ) {
-        newScaffoldingIdx--
-        moved = true
-      }
     }
   }