fix(docs): put-md upsert by stem to avoid duplicate folder files

UploadToFolderReplacing deletes same-stem files before upload (--replace,
default true). OO may still display title+fileExst as double extension.

Co-authored-by: Cursor <cursoragent@cursor.com>

files_stem_test.go

@@ -0,0 +1,35 @@
+package onlyoffice
+
+import "testing"
+
+func TestNormalizeUploadStem(t *testing.T) {
+	tests := []struct {
+		title, exst, want string
+	}{
+		{"OO-HONDA-7-INDEX.docx", ".docx", "OO-HONDA-7-INDEX"},
+		{"README.txt", ".txt", "README"},
+		{"car-docs-print.docx", ".docx", "car-docs-print"},
+		{"plain.", "", "plain"},
+		{"foo", ".docx", "foo"},
+	}
+	for _, tc := range tests {
+		if got := NormalizeUploadStem(tc.title, tc.exst); got != tc.want {
+			t.Fatalf("NormalizeUploadStem(%q,%q)=%q want %q", tc.title, tc.exst, got, tc.want)
+		}
+	}
+}
+
+func TestFileEntryStem(t *testing.T) {
+	title := "00-INDEX.docx"
+	exst := ".docx"
+	f := &FileEntry{Title: &title, FileExst: &exst}
+	if got := FileEntryStem(f); got != "00-INDEX" {
+		t.Fatalf("got %q", got)
+	}
+}
+
+func TestUploadStemFromLocal(t *testing.T) {
+	if got := UploadStemFromLocal("/tmp/OO-HONDA-7-INDEX.docx"); got != "OO-HONDA-7-INDEX" {
+		t.Fatalf("got %q", got)
+	}
+}