test: add comprehensive test suite for components, composables, and pages

Add 16 new test files covering:
- Composables: useBackend, useMeta, useDataJson
- Type classes: QueryResult, ResumeContent
- UI components: BadgeList, BadgeListCard
- Navbar components: LanguageSwitcher, ThemeSwitcher
- App components: AppNavbar, AppFooter
- VocalSynth components: Projects, Tools
- Pages: contact, resume, [...slug]

Tests focus on pure logic, interfaces, and component rendering where
possible, avoiding complex mocking of Nuxt auto-imported composables.

Total: 174 tests across 17 test files (including existing useApi tests).

app/types/resume.test.ts

@@ -0,0 +1,129 @@
+import { describe, it, expect } from 'vitest';
+import { ResumeExperience, ResumeContent } from './resume';
+import type { Tool } from './tool';
+
+describe('ResumeExperience', () => {
+  describe('initialization', () => {
+    it('should initialize with empty tools array', () => {
+      const experience = new ResumeExperience();
+      expect(experience.tools).toEqual([]);
+    });
+
+    it('should initialize with undefined description', () => {
+      const experience = new ResumeExperience();
+      expect(experience.description).toBeUndefined();
+    });
+  });
+
+  describe('property assignment', () => {
+    it('should allow tools to be assigned', () => {
+      const experience = new ResumeExperience();
+      const tools: Tool[] = [{ name: 'TypeScript', link: 'https://typescriptlang.org' }, { name: 'Vue.js' }];
+      experience.tools = tools;
+      expect(experience.tools).toEqual(tools);
+    });
+
+    it('should allow description to be assigned', () => {
+      const experience = new ResumeExperience();
+      experience.description = 'Software developer working on web applications';
+      expect(experience.description).toBe('Software developer working on web applications');
+    });
+  });
+
+  describe('TimelineItem interface implementation', () => {
+    it('should be usable as TimelineItem', () => {
+      const experience = new ResumeExperience();
+      // TimelineItem interface from @nuxt/ui - ResumeExperience implements it
+      expect(experience).toHaveProperty('tools');
+      expect(experience).toHaveProperty('description');
+    });
+  });
+});
+
+describe('ResumeContent', () => {
+  describe('initialization', () => {
+    it('should initialize with empty experience array', () => {
+      const content = new ResumeContent();
+      expect(content.experience).toEqual([]);
+    });
+
+    it('should initialize with empty education array', () => {
+      const content = new ResumeContent();
+      expect(content.education).toEqual([]);
+    });
+
+    it('should initialize with empty otherTools array', () => {
+      const content = new ResumeContent();
+      expect(content.otherTools).toEqual([]);
+    });
+
+    it('should initialize with empty devops array', () => {
+      const content = new ResumeContent();
+      expect(content.devops).toEqual([]);
+    });
+
+    it('should initialize with empty os array', () => {
+      const content = new ResumeContent();
+      expect(content.os).toEqual([]);
+    });
+
+    it('should initialize with empty programmingLanguages array', () => {
+      const content = new ResumeContent();
+      expect(content.programmingLanguages).toEqual([]);
+    });
+
+    it('should initialize with empty frameworks array', () => {
+      const content = new ResumeContent();
+      expect(content.frameworks).toEqual([]);
+    });
+  });
+
+  describe('property assignment', () => {
+    it('should allow experience to be assigned', () => {
+      const content = new ResumeContent();
+      const exp = new ResumeExperience();
+      exp.description = 'Test job';
+      content.experience = [exp];
+      expect(content.experience.length).toBe(1);
+      expect(content.experience[0].description).toBe('Test job');
+    });
+
+    it('should allow tools arrays to be assigned', () => {
+      const content = new ResumeContent();
+      const tools: Tool[] = [{ name: 'Git', link: 'https://git-scm.com' }];
+
+      content.devops = tools;
+      content.os = [{ name: 'Linux' }];
+      content.programmingLanguages = [{ name: 'Rust', link: 'https://rust-lang.org' }];
+      content.frameworks = [{ name: 'Nuxt', link: 'https://nuxt.com' }];
+      content.otherTools = [{ name: 'Vim' }];
+
+      expect(content.devops).toEqual(tools);
+      expect(content.os).toEqual([{ name: 'Linux' }]);
+      expect(content.programmingLanguages).toEqual([{ name: 'Rust', link: 'https://rust-lang.org' }]);
+      expect(content.frameworks).toEqual([{ name: 'Nuxt', link: 'https://nuxt.com' }]);
+      expect(content.otherTools).toEqual([{ name: 'Vim' }]);
+    });
+
+    it('should allow education to be assigned', () => {
+      const content = new ResumeContent();
+      content.education = [{ title: 'Computer Science', description: 'Master degree' }];
+      expect(content.education.length).toBe(1);
+    });
+  });
+
+  describe('default values', () => {
+    it('should provide safe defaults when used without data', () => {
+      const content = new ResumeContent();
+
+      // All arrays should be empty but defined
+      expect(Array.isArray(content.experience)).toBe(true);
+      expect(Array.isArray(content.education)).toBe(true);
+      expect(Array.isArray(content.otherTools)).toBe(true);
+      expect(Array.isArray(content.devops)).toBe(true);
+      expect(Array.isArray(content.os)).toBe(true);
+      expect(Array.isArray(content.programmingLanguages)).toBe(true);
+      expect(Array.isArray(content.frameworks)).toBe(true);
+    });
+  });
+});