init: lib-core.api-discovery-test v0.1.0 skeleton

Empty run_tests body. Assertions added incrementally via TDD in
subsequent S2-plan tasks.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

init.lua

@@ -0,0 +1,12 @@
+-- lib-core.api-discovery-test — Test-lib for lib-core.api-discovery
+local api = require("lib-core.api-discovery")
+
+local M = {}
+
+function M.run_tests(ctx)
+    -- Assertions added in plan tasks 2-7.
+
+    engine.exit(engine.test.failures())
+end
+
+return M