feat: add VCF to CSV converter

Add support for converting VCF contact files to CSV format
- Implement TypeScript-based VCF parsing without external dependencies
- Create CSV export with proper quote escaping
- Add comprehensive test coverage for various VCF formats
- Update documentation and converter registry

Closes #396

tests/converters/vcf.test.ts

@@ -0,0 +1,103 @@
+import { expect, test, describe } from "bun:test";
+import { convert, parseVCF, toCSV } from "../../src/converters/vcf";
+
+describe("parseVCF", () => {
+  test("should parse a simple VCF card", () => {
+    const vcfData = `BEGIN:VCARD
+VERSION:3.0
+FN:John Doe
+N:Doe;John;;;
+TEL:+123456789
+EMAIL:john@example.com
+ORG:Example Corp
+END:VCARD`;
+
+    const result = parseVCF(vcfData);
+
+    expect(result).toEqual([
+      {
+        'Full Name': 'John Doe',
+        'Last Name': 'Doe',
+        'First Name': 'John',
+        'Phone': '+123456789',
+        'Email': 'john@example.com',
+        'Organization': 'Example Corp'
+      }
+    ]);
+  });
+
+  test("should handle multiple cards", () => {
+    const vcfData = `BEGIN:VCARD
+FN:John Doe
+END:VCARD
+BEGIN:VCARD
+FN:Jane Smith
+END:VCARD`;
+
+    const result = parseVCF(vcfData);
+
+    expect(result).toEqual([
+      { 'Full Name': 'John Doe' },
+      { 'Full Name': 'Jane Smith' }
+    ]);
+  });
+
+  test("should parse VCF with TYPE parameters", () => {
+    const vcfData = `BEGIN:VCARD
+VERSION:3.0
+FN:John Doe
+N:Doe;John;;;
+TEL;TYPE=WORK,VOICE:(111) 555-1212
+EMAIL;TYPE=PREF,INTERNET:john.doe@example.com
+END:VCARD`;
+
+    const result = parseVCF(vcfData);
+
+    expect(result).toEqual([
+      {
+        'Full Name': 'John Doe',
+        'Last Name': 'Doe',
+        'First Name': 'John',
+        'Phone': '(111) 555-1212',
+        'Email': 'john.doe@example.com'
+      }
+    ]);
+  });
+});
+
+describe("toCSV", () => {
+  test("should convert contacts to CSV", () => {
+    const contacts = [
+      {
+        'Full Name': 'John Doe',
+        'Phone': '+123',
+        'Email': 'john@example.com'
+      }
+    ];
+
+    const result = toCSV(contacts);
+
+    expect(result).toBe('Full Name,Phone,Email\n"John Doe","+123","john@example.com"');
+  });
+
+  test("should escape quotes", () => {
+    const contacts = [
+      { 'Full Name': 'John "Johnny" Doe' }
+    ];
+
+    const result = toCSV(contacts);
+
+    expect(result).toBe('Full Name\n"John ""Johnny"" Doe"');
+  });
+
+  test("should handle empty data", () => {
+    const result = toCSV([]);
+    expect(result).toBe('');
+  });
+});
+
+describe("convert", () => {
+  test("should be a function", () => {
+    expect(typeof convert).toBe("function");
+  });
+});