fix(filemerge): follow symlinked parent directories instead of refusing

internal/components/filemerge/writer.go

@@ -150,7 +150,17 @@ func ensureAtomicParentDir(dir, path string) error {
 		return fmt.Errorf("stat parent directory for %q: %w", path, err)
 	}
 	if info.Mode()&os.ModeSymlink != 0 {
-		return fmt.Errorf("refusing symlink parent directory %q for %q", dir, path)
+		// Parent is a symlink (e.g. ~/.claude/agents → dotfiles repo).
+		// Resolve the target and continue checks against the real directory.
+		resolved, err := filepath.EvalSymlinks(dir)
+		if err != nil {
+			return fmt.Errorf("resolving symlink parent %q for %q: %w", dir, path, err)
+		}
+		info, err = os.Stat(resolved)
+		if err != nil {
+			return fmt.Errorf("stat symlink target %q for %q: %w", resolved, path, err)
+		}
+		dir = resolved
 	}
 	if !info.IsDir() {
 		return fmt.Errorf("parent path %q for %q is not a directory", dir, path)

internal/components/filemerge/writer_test.go

@@ -1,6 +1,7 @@
 package filemerge
 
 import (
+	"bytes"
 	"errors"
 	"os"
 	"path/filepath"
@@ -125,7 +126,7 @@ func TestWriteFileAtomicRejectsOversizedExistingFile(t *testing.T) {
 	}
 }
 
-func TestWriteFileAtomicRejectsSymlinkParentDirectory(t *testing.T) {
+func TestWriteFileAtomicFollowsSymlinkParentDirectory(t *testing.T) {
 	base := t.TempDir()
 	realDir := filepath.Join(base, "real")
 	if err := os.Mkdir(realDir, 0o755); err != nil {
@@ -142,10 +143,23 @@ func TestWriteFileAtomicRejectsSymlinkParentDirectory(t *testing.T) {
 		t.Fatalf("Symlink(linkDir) error = %v", err)
 	}
 
+	// Writing through a symlinked parent (e.g. ~/.claude/agents → dotfiles repo)
+	// must succeed: the file lands in the real directory.
+	content := []byte("value\n")
 	path := filepath.Join(linkDir, "config.txt")
-	_, err := WriteFileAtomic(path, []byte("value\n"), 0o644)
-	if err == nil {
-		t.Fatal("WriteFileAtomic() error = nil, want symlink parent rejection")
+	_, err := WriteFileAtomic(path, content, 0o644)
+	if err != nil {
+		t.Fatalf("WriteFileAtomic() via symlink parent error = %v, want success", err)
+	}
+
+	// Verify the file was written to the real directory.
+	realPath := filepath.Join(realDir, "config.txt")
+	got, readErr := os.ReadFile(realPath)
+	if readErr != nil {
+		t.Fatalf("ReadFile(realPath) error = %v", readErr)
+	}
+	if !bytes.Equal(got, content) {
+		t.Fatalf("content = %q, want %q", got, content)
 	}
 }