feat: implement MoloApp plans 01-15 with integration

Full C++23 framework tree: runtime, observability, security,
data, app, realtime, supervisor, clients, CLI, example plus
enterprise tenancy, audit, operability, governance,
supplychain. Postgres via docker compose for tests.

tests/example/chain/deep_test.cpp

@@ -0,0 +1,14 @@
+// Route: /app1/app1/app1/whoami  (application chaining, depth 3)
+#include "support/Assert.hpp"
+
+using namespace molo::example::test;
+
+int main() {
+  Fixture f;
+  auto res = f.client->get("/app1/app1/app1/whoami");
+  check(res.status == 200, "status 200");
+  check(contains(res.body, "\"depth\":3"), "three mounts merged");
+  auto shallow = f.client->get("/app1/whoami");
+  check(shallow.status == 404, "partial chain is 404");
+  return finish("chain/deep");
+}