cmake: add FindGrantlee5.cmake shim to gracefully skip Grantlee when unavailable (avoids Qt5/Qt6 mixing)\n\nCo-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

cmake/FindGrantlee5.cmake

@@ -0,0 +1,23 @@
+# Minimal Find module for Grantlee5 to allow configure to continue when not installed
+# This intentionally does not attempt to build or provide Qt5-based Grantlee
+# If a Qt6-compatible Grantlee is available, set Grantlee5_DIR or install the package
+
+if (TARGET Grantlee5::Templates)
+  set(Grantlee5_FOUND TRUE)
+  return()
+endif()
+
+# Try pkg-config as a best-effort (may fail)
+find_package(PkgConfig QUIET)
+if (PKG_CONFIG_FOUND)
+  pkg_check_modules(GRANTLEE5 QUIET grantlee-templates)
+  if (GRANTLEE5_FOUND)
+    set(Grantlee5_FOUND TRUE)
+    # No imported targets provided by this shim
+    return()
+  endif()
+endif()
+
+# Not found: provide helpful message and stop. Downstream CMakeLists check TARGET Grantlee5::Templates
+set(Grantlee5_FOUND FALSE)
+message(STATUS "Grantlee5 not found (shim cmake/FindGrantlee5.cmake); codegen_grantlee will be skipped if present.")