lib-core.git-test v0.1.0: smoke test for the libgit2 wrapper

Exercises the sync API (clone, is_repo, describe, tags) against a
public Gitea repo over HTTPS, plus the async ls_remote_tags handshake
through the engine async-pool. Designed for SPOREL_CI runs: kicks off
the async work in init(), polls in update(), calls engine.exit(0)
once the result has been taken.

manifest.core

@@ -0,0 +1,6 @@
+{
+    "id": "lib-core.git-test.core",
+    "kind": "lib",
+    "version": "0.1.0",
+    "license": "Proprietary"
+}