Optimize simulation with logic-only solver, fix rectangular grid support, and improve worker pool

src/utils/repro_solver.test.js

@@ -0,0 +1,49 @@
+
+import { describe, it, expect } from 'vitest';
+import { solvePuzzle } from './solver';
+import { calculateHints } from './puzzleUtils';
+
+describe('Solver Repro', () => {
+    it('should solve a simple generated puzzle', () => {
+        const grid = [
+            [1, 0, 1, 1, 0],
+            [1, 1, 0, 0, 1],
+            [0, 0, 1, 0, 0],
+            [1, 1, 1, 1, 1],
+            [0, 1, 0, 1, 0]
+        ];
+        const { rowHints, colHints } = calculateHints(grid);
+        
+        const result = solvePuzzle(rowHints, colHints);
+        expect(result.percentSolved).toBe(100);
+    });
+
+    it('should not fail on random valid lines', () => {
+        // Test solveLine indirectly via solvePuzzle on small grids
+        for (let i = 0; i < 100; i++) {
+            const size = 10;
+            const grid = [];
+            for(let r=0; r<size; r++) {
+                const row = [];
+                for(let c=0; c<size; c++) row.push(Math.random() > 0.5 ? 1 : 0);
+                grid.push(row);
+            }
+            
+            const { rowHints, colHints } = calculateHints(grid);
+            const result = solvePuzzle(rowHints, colHints);
+            
+            // It might not be 100% solvable without guessing (logic only), 
+            // but since our solver HAS backtracking, it MUST be 100% solvable 
+            // (unless timeout/max depth reached, but for 10x10 it should solve).
+            
+            // If it returns 0% or low %, it implies it failed to find the solution 
+            // or found a contradiction (which shouldn't happen for valid hints).
+            
+            if (result.percentSolved < 100) {
+                console.log('Failed Grid:', JSON.stringify(grid));
+                console.log('Result:', result);
+            }
+            expect(result.percentSolved).toBe(100);
+        }
+    });
+});