upgrade ACTS from v36 to v47

CMakeLists.txt

@@ -71,6 +71,31 @@ find_package(
              atomic
              regex)
 
+# Find Eigen3 (required by ACTS)
+find_package(Eigen3 CONFIG REQUIRED)
+
+# GNUInstallDirs must be included before ACTS is configured as a sub-project;
+# ACTS only calls include(GNUInstallDirs) when it is the top-level project, so
+# CMAKE_INSTALL_INCLUDEDIR would otherwise be empty and its install() calls fail.
+include(GNUInstallDirs)
+
+# Find or fetch ACTS - must be at top level so both Ecal and Tracking can use it
+find_package(Acts 47.0.0 QUIET)
+if (NOT Acts_FOUND)
+  message(STATUS "Did not find Acts >= 47.0.0, downloading and compiling v47.0.0")
+  include(FetchContent)
+  FetchContent_Declare(
+      Acts
+      URL https://github.com/acts-project/acts/archive/refs/tags/v47.0.0.tar.gz
+      URL_HASH MD5=833c02edee49827f25be74c80d8ee654
+      DOWNLOAD_EXTRACT_TIMESTAMP TRUE
+  )
+  FetchContent_MakeAvailable(Acts)
+  FetchContent_GetProperties(Acts)
+  include_directories(SYSTEM "${Acts_SOURCE_DIR}/Core/include")
+else()
+  message(STATUS "Found Acts ${Acts_VERSION}")
+endif()
 
 # FunctionalCoreTest.cxx doesnt comply with clang-tidy but that's ok
 set_source_files_properties(Framework/test/FunctionalCoreTest.cxx PROPERTIES COMPILE_OPTIONS "-Wno-null-dereference")

Ecal/CMakeLists.txt

@@ -17,15 +17,13 @@ setup_library(
 find_package(ONNXRuntime 1.2.0)
 
 find_package(Eigen3 CONFIG REQUIRED)
-
-# Find ACTS for track finding in ECAL
-find_package(Acts REQUIRED COMPONENTS Core)
+# Acts is set up by the top-level CMakeLists.txt
 
 setup_library(module Ecal
               dependencies ROOT::Physics
                            Framework::Framework Recon::Event Recon::Recon Tools::Tools DetDescr::DetDescr
                            ONNXRuntime::Interface Ecal::Event Tracking::Event Tracking::Tracking SimCore::Event
-                           Eigen3::Eigen ActsCore
+                           Eigen3::Eigen Acts::Core
 )
 
 setup_test(dependencies Ecal::Ecal)

Ecal/include/Ecal/EcalTrackFinderProcessor.h

@@ -35,6 +35,8 @@
 #include "Acts/Surfaces/RectangleBounds.hpp"
 #include "Acts/Surfaces/Surface.hpp"
 #include "Acts/TrackFinding/CombinatorialKalmanFilter.hpp"
+#include "Acts/TrackFinding/MeasurementSelector.hpp"
+#include "Acts/TrackFinding/TrackStateCreator.hpp"
 #include "Acts/TrackFitting/GainMatrixUpdater.hpp"
 
 // C++