feat: add buildFileUrl utility with tests

Moved from ProjectsSection inline function to shared/lib/utils.
Accepts optional baseUrl for testability without env mocking.

src/shared/lib/index.ts

@@ -1,6 +1,7 @@
 export type { ClassValue } from 'clsx';
 export { CONTACT_LINKS } from './config/config';
 export * from './fonts/fonts';
+export { buildFileUrl } from './utils/buildFileUrl/buildFileUrl';
 export { cn } from './utils/cn/cn';
 export * from './utils/formatDate/formatDate';
 export { groupByKey } from './utils/groupByKey/groupByKey';

src/shared/lib/utils/buildFileUrl/buildFileUrl.test.ts

@@ -0,0 +1,33 @@
+import { buildFileUrl } from './buildFileUrl';
+
+describe('buildFileUrl', () => {
+  describe('default base URL', () => {
+    it('builds correct URL with default base', () => {
+      expect(buildFileUrl('site_settings', 'ss1', 'cv_2024.pdf')).toBe(
+        'http://127.0.0.1:8090/api/files/site_settings/ss1/cv_2024.pdf',
+      );
+    });
+  });
+
+  describe('custom base URL', () => {
+    it('uses provided baseUrl when given', () => {
+      expect(buildFileUrl('photos', 'rec1', 'avatar.png', 'https://pb.example.com')).toBe(
+        'https://pb.example.com/api/files/photos/rec1/avatar.png',
+      );
+    });
+  });
+
+  describe('different collections, records, filenames', () => {
+    it('handles projects collection', () => {
+      expect(buildFileUrl('projects', 'proj42', 'screenshot.jpg', 'http://127.0.0.1:8090')).toBe(
+        'http://127.0.0.1:8090/api/files/projects/proj42/screenshot.jpg',
+      );
+    });
+
+    it('handles contacts collection', () => {
+      expect(buildFileUrl('contacts', 'cid99', 'photo.webp', 'http://127.0.0.1:8090')).toBe(
+        'http://127.0.0.1:8090/api/files/contacts/cid99/photo.webp',
+      );
+    });
+  });
+});

src/shared/lib/utils/buildFileUrl/buildFileUrl.ts

@@ -0,0 +1,11 @@
+/**
+ * Builds a URL for a file stored in a PocketBase record.
+ */
+export function buildFileUrl(
+  collectionId: string,
+  recordId: string,
+  filename: string,
+  baseUrl: string = process.env.NEXT_PUBLIC_PB_URL ?? 'http://127.0.0.1:8090',
+): string {
+  return `${baseUrl}/api/files/${collectionId}/${recordId}/${filename}`;
+}