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/sessions/counter_test.cpp

@@ -0,0 +1,17 @@
+// Route: GET /sessions/counter  (signed cookie session)
+#include "support/Assert.hpp"
+
+using namespace molo::example::test;
+
+int main() {
+  Fixture f;
+  auto first = f.client->get("/sessions/counter");
+  check(first.status == 200, "status 200");
+  check(contains(first.body, "\"count\":1"), "counter starts at 1");
+  check(contains(first.body, "\"fresh\":true"), "first visit is fresh");
+  check(first.headers.has("Set-Cookie"), "session cookie set");
+  auto second = f.client->get("/sessions/counter");
+  check(contains(second.body, "\"count\":2"), "jar keeps session");
+  check(contains(second.body, "\"fresh\":false"), "second visit resumes");
+  return finish("sessions/counter");
+}