Release 2.7.2+1: stop auto-apply update loop; check-only on start, apply on button with skip/opt-in.

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

internal/update/update_test.go

@@ -15,6 +15,19 @@ func TestCompare(t *testing.T) {
 	if Compare("1.1.0", "1.1.0") != 0 {
 		t.Fatal("expected equal")
 	}
+	// Build must not make same product look outdated or newer for update checks.
+	if Compare("2.7.2", "2.7.2+9") != 0 {
+		t.Fatal("expected equal ignoring +build")
+	}
+	if Compare("2.7.2", "2.7.2.99") != 0 {
+		t.Fatal("expected equal ignoring 4th component")
+	}
+	if Compare("2.7.3", "2.7.2+1") <= 0 {
+		t.Fatal("expected product bump to win")
+	}
+	if DisplayVersion() == "" || !strings.Contains(DisplayVersion(), "+") {
+		t.Fatal("DisplayVersion should include build")
+	}
 }
 
 func TestManifestAssetFor(t *testing.T) {