feat: represent symlink diffs as link targets

Untracked symlinks now show as link entries in diff output.
File diffs display symlink targets instead of following them.
Added tests for patch and split diff behavior.

packages/web/server/lib/git/service.test.js

@@ -22,6 +22,7 @@ import {
   unstageFiles,
   applyHunk,
   getDiff,
+  getFileDiff,
 } from './service.js';
 
 // ---------------------------------------------------------------------------
@@ -264,6 +265,26 @@ describe('applyHunk', () => {
   });
 });
 
+describe('symlink diffs', () => {
+  it('treats an untracked directory symlink as a link in patch and split diffs', async () => {
+    if (!canRunGit() || process.platform === 'win32') return;
+    const { tmpDir } = await createTempRepo();
+    fs.mkdirSync(path.join(tmpDir, 'source'));
+    fs.symlinkSync('source', path.join(tmpDir, 'linked-source'));
+
+    const patch = await getDiff(tmpDir, { path: 'linked-source' });
+    const split = await getFileDiff(tmpDir, { path: 'linked-source' });
+
+    expect(patch).toContain('new file mode 120000');
+    expect(patch).toContain('+source');
+    expect(split).toMatchObject({
+      original: '',
+      modified: 'source',
+      isBinary: false,
+    });
+  });
+});
+
 // ---------------------------------------------------------------------------
 // getStatus
 // ---------------------------------------------------------------------------