feat: add candidate FreeCAD naming SDK and attachment oracles

Build and verify the candidate-only FreeCAD naming bridge and OCCT worker path, including three-stage StringHasher restoration. Add Datum, ShapeBinder, attachment-mode, and PartDesign structure oracles plus offline SDK build plans and CI boundary checks.

config/cmake/fmt/fmt-config.cmake

@@ -0,0 +1,17 @@
+if(NOT FREECAD_WASM_OFFLINE_SYSROOT)
+    message(FATAL_ERROR "FREECAD_WASM_OFFLINE_SYSROOT is required by the candidate fmt package")
+endif()
+set(_freecad_wasm_fmt_include "${FREECAD_WASM_OFFLINE_SYSROOT}/fmt-10.1.1/include")
+if(NOT EXISTS "${_freecad_wasm_fmt_include}/fmt/format.h")
+    message(FATAL_ERROR "Offline fmt headers are missing: ${_freecad_wasm_fmt_include}/fmt/format.h")
+endif()
+if(NOT TARGET fmt)
+    add_library(fmt INTERFACE)
+    target_include_directories(fmt INTERFACE "${_freecad_wasm_fmt_include}")
+    target_compile_definitions(fmt INTERFACE FMT_HEADER_ONLY=1)
+endif()
+if(NOT TARGET fmt::fmt)
+    add_library(fmt::fmt ALIAS fmt)
+endif()
+set(fmt_FOUND TRUE)
+set(fmt_VERSION 10.1.1)