Staging 2: Onboarding, settings and block clock

[johnny9]

This is the second staging PR for the QML-based Bitcoin Core GUI. It builds on #871.

This draft targets current staging, which includes #871. Its diff contains the Chunk 2 changes and the macOS QML deployment follow-up. Review the changes here.

This PR focuses on onboarding, settings and the block clock, without wallet support. Users can configure a node, follow synchronization, change settings and shut down safely.

Main decisions

• Use one shell and router for pages, the global menu and native menu/tray actions.
• Load translations before onboarding.
• Preserve Core settings precedence, active-profile handling, backups and rollback.
• Keep lifecycle, synchronization, connection state and runtime dialogs in focused models.
• Include the window behavior and display settings needed by these flows.
• Leave RPC, debug log, peers/bans, traffic and mempool tools for Chunk 3. Add money-font and explorer-link preferences with their wallet consumers later.

Test coverage

C++ unit, QML and in-process integration tests cover the feature regressions. A separate process test checks ordinary startup errors. One short Python bridge journey covers the running block clock, settings navigation and clean shutdown; the inherited TestShell check covers fresh onboarding and process cleanup.

Local checks pass on Linux with Qt 6.8.4, with wallets compiled out, for both bitcoin-qt and IPC bitcoin-gui. Native desktop interactions and other Qt/platform versions remain separate checks.

[hebasto]

I think this code

gui-qml/src/qt/CMakeLists.txt

Lines 5 to 12 in 3e949c5

	if(CMAKE_SYSTEM_NAME STREQUAL "Darwin")
	enable_language(OBJCXX)
	set(CMAKE_OBJCXX_FLAGS_RELWITHDEBINFO "${CMAKE_CXX_FLAGS_RELWITHDEBINFO}")
	set(CMAKE_OBJCXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE}")
	set(CMAKE_OBJCXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG}")
	set(CMAKE_OBJCXX_FLAGS_MINSIZEREL "${CMAKE_CXX_FLAGS_MINSIZEREL}")
	string(APPEND CMAKE_OBJCXX_COMPILE_OBJECT " ${APPEND_CPPFLAGS} ${APPEND_CXXFLAGS}")
	endif()

should be copied to qml/CMakeLists.txt

[hebasto]

Please rebase on top of the updated staging branch.