feat: add Flathub mirror support

test/platforms/flathub.test.js

@@ -0,0 +1,56 @@
+import { describe, expect, it } from 'vitest';
+import { PLATFORMS, transformPath } from '../../src/config/platforms.js';
+
+describe('Flathub Platform Configuration', () => {
+  it('should have Flathub platform configured', () => {
+    expect(PLATFORMS.flathub).toBe('https://dl.flathub.org');
+  });
+
+  it('should transform Flathub repository paths correctly', () => {
+    const testCases = [
+      {
+        input: '/flathub/repo/summary',
+        expected: '/repo/summary',
+        description: 'repository summary'
+      },
+      {
+        input: '/flathub/repo/summary.sig',
+        expected: '/repo/summary.sig',
+        description: 'repository summary signature'
+      },
+      {
+        input: '/flathub/repo/flathub.flatpakrepo',
+        expected: '/repo/flathub.flatpakrepo',
+        description: 'remote descriptor'
+      },
+      {
+        input: '/flathub/repo/appstream/org.gnome.gedit.flatpakref',
+        expected: '/repo/appstream/org.gnome.gedit.flatpakref',
+        description: 'application reference'
+      },
+      {
+        input: '/flathub/repo/objects/12/34567890abcdef.filez',
+        expected: '/repo/objects/12/34567890abcdef.filez',
+        description: 'content-addressed object'
+      },
+      {
+        input: '/flathub/repo/deltas/ABCD.superblock',
+        expected: '/repo/deltas/ABCD.superblock',
+        description: 'static delta'
+      }
+    ];
+
+    testCases.forEach(({ input, expected, description }) => {
+      const result = transformPath(input, 'flathub');
+      expect(result, `Failed for ${description}: ${input}`).toBe(expected);
+    });
+  });
+
+  it('should handle root path correctly', () => {
+    expect(transformPath('/flathub/', 'flathub')).toBe('/');
+  });
+
+  it('should preserve already transformed Flathub repository paths', () => {
+    expect(transformPath('/repo/summary', 'flathub')).toBe('/repo/summary');
+  });
+});