Fix CMake build structure and add usage docs

Focus on consumers using submodules + add_subdirectory, pruning logic related to local installation for now. Targets are now namespaced properly in `InkStrokeModeler::`.

Adds usage documentation for consuming the library from Bazel and CMake projects.

PiperOrigin-RevId: 433015667

1 files changed, 1 insertions, 0 deletions

diff --git a/BUILD b/BUILD
index f8433a5..cefdd4d 100644
--- a/BUILD
+++ b/BUILD
@@ -24,4 +24,5 @@ alias(
     name = "gtest_for_library_testonly",
     testonly = 1,
     actual = "@com_google_googletest//:gtest",
+    visibility = ["//:__subpackages__"],
 )