initial: notify-test v0.1.0 — 13 assertions

Tests: channel create/list round-trip, tag-match routing, non-match
exclusion, catch-all (empty filter), subscribe callback, unsubscribe,
post-without-tags error, empty-tags error, duplicate-channel error,
unknown-display-mode error, ring-buffer cap, engine-log-mirror toggle,
and severity sugar (warn/info).

manifest.lib

@@ -0,0 +1,9 @@
+{
+    "id": "lib-core.notify-test",
+    "role": "test",
+    "version": "0.1.0",
+    "api_min": "0.1",
+    "deps": [
+        {"id": "lib-core.notify", "version": "0.1.0"}
+    ]
+}