create initial structure + cmakelists (thanks claude)

cmake/bravaisConfig.cmake.in

@@ -0,0 +1,18 @@
+@PACKAGE_INIT@
+
+include(CMakeFindDependencyMacro)
+
+# libsodium and liboqs are PRIVATE link dependencies, so a consumer of the
+# shared library never sees them. A consumer of the *static* library does: the
+# archive carries unresolved crypto_* and OQS_* symbols that only the final link
+# line can satisfy, and CMake recorded them as $<LINK_ONLY:...> in the export
+# set. Resolve them here so `find_package(bravais)` works for both.
+if(@BRAVAIS_ENABLE_CRYPTO@)
+    find_dependency(PkgConfig)
+    pkg_check_modules(SODIUM REQUIRED IMPORTED_TARGET libsodium>=1.0.18)
+    find_dependency(liboqs CONFIG)
+endif()
+
+include("${CMAKE_CURRENT_LIST_DIR}/bravaisTargets.cmake")
+
+check_required_components(bravais)