feat(BRIDGE-356): Added retry logic for unavailable preferred keychain on Linux; Feature flag support before bridge initialization; Refactored some bits of the code;

internal/platform/platform.go

@@ -0,0 +1,24 @@
+// Copyright (c) 2025 Proton AG
+//
+// This file is part of Proton Mail Bridge.
+//
+// Proton Mail Bridge is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Proton Mail Bridge is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Proton Mail Bridge. If not, see <https://www.gnu.org/licenses/>.
+
+package platform
+
+const (
+	MACOS   = "darwin"
+	LINUX   = "linux"
+	WINDOWS = "windows"
+)