feat(test): add comprehensive test suite and testing infrastructure

- Add vitest configuration with coverage reporting
- Create test setup file with DOM mocks
- Add tests for state management, helpers, and tool configurations
- Update tsconfig and package.json for testing support
- Clean up unused comments and improve code style

src/tests/pdf-tools.test.ts

@@ -0,0 +1,86 @@
+import { describe, it, expect } from 'vitest';
+import { singlePdfLoadTools, simpleTools, multiFileTools } from '@/js/config/pdf-tools';
+
+describe('Tool Configuration Arrays', () => {
+
+  // --- Tests for singlePdfLoadTools ---
+  describe('singlePdfLoadTools', () => {
+    it('should be an array of non-empty strings', () => {
+      expect(Array.isArray(singlePdfLoadTools)).toBe(true);
+      expect(singlePdfLoadTools.length).toBeGreaterThan(0);
+      for (const tool of singlePdfLoadTools) {
+        expect(typeof tool).toBe('string');
+        expect(tool.length).toBeGreaterThan(0);
+      }
+    });
+
+    it('should have the correct number of tools', () => {
+      // This acts as a snapshot test to catch unexpected additions/removals.
+      expect(singlePdfLoadTools).toHaveLength(37);
+    });
+
+    it('should not contain any duplicate tools', () => {
+      const uniqueTools = new Set(singlePdfLoadTools);
+      expect(uniqueTools.size).toBe(singlePdfLoadTools.length);
+    });
+  });
+
+  // --- Tests for simpleTools ---
+  describe('simpleTools', () => {
+    it('should be an array of non-empty strings', () => {
+      expect(Array.isArray(simpleTools)).toBe(true);
+      expect(simpleTools.length).toBeGreaterThan(0);
+      simpleTools.forEach(tool => {
+        expect(typeof tool).toBe('string');
+        expect(tool.length).toBeGreaterThan(0);
+      });
+    });
+
+    it('should have the correct number of tools', () => {
+      expect(simpleTools).toHaveLength(5);
+    });
+
+    it('should not contain any duplicate tools', () => {
+      const uniqueTools = new Set(simpleTools);
+      expect(uniqueTools.size).toBe(simpleTools.length);
+    });
+  });
+
+  // --- Tests for multiFileTools ---
+  describe('multiFileTools', () => {
+    it('should be an array of non-empty strings', () => {
+      expect(Array.isArray(multiFileTools)).toBe(true);
+      expect(multiFileTools.length).toBeGreaterThan(0);
+      multiFileTools.forEach(tool => {
+        expect(typeof tool).toBe('string');
+        expect(tool.length).toBeGreaterThan(0);
+      });
+    });
+
+    it('should have the correct number of tools', () => {
+      expect(multiFileTools).toHaveLength(10);
+    });
+
+    it('should not contain any duplicate tools', () => {
+      const uniqueTools = new Set(multiFileTools);
+      expect(uniqueTools.size).toBe(multiFileTools.length);
+    });
+  });
+
+  // --- Cross-Category Uniqueness Test ---
+  describe('Uniqueness Across All Tool Categories', () => {
+    it('should ensure no tool exists in more than one category', () => {
+      const allTools = [
+        ...singlePdfLoadTools,
+        ...simpleTools,
+        ...multiFileTools,
+      ];
+      const uniqueTools = new Set(allTools);
+
+      // If the size of the Set is different from the length of the combined array,
+      // it means there was at least one duplicate tool across the categories.
+      expect(uniqueTools.size).toBe(allTools.length);
+    });
+  });
+
+});