tutorial-v3: a 'core' module that consumes delivery_module crashes — document the ui_qml-backend path (refs delivery#31, basecamp#150)

[xAlisher]

Summary

Following the tutorial-v3 canonical architecture — a type: core module (Part 1) + a QML UI (Part 2) — leads to a hard runtime crash as soon as the core module tries to consume delivery_module. The tutorial presents core+QML as the default and frames the ui_qml-with-C++-backend (Part 3) as the heavier/optional path, but for anything that consumes delivery_module the ui_qml C++ backend is the only working path. This isn't documented anywhere except an open issue, so it's a day-one trap for downstream devs.

What happens

In the core plugin's initLogos, constructing the generated typed SDK crashes before any of my own calls run:

void RadioPlugin::initLogos(LogosAPI* api) {
    logosAPI = api;
    m_logos  = new LogosModules(api);   // 💥 std::length_error
}

terminate called after throwing an instance of 'std::length_error'
  what():  basic_string::_M_create
#0  std::__cxx11::basic_string<...>::_M_construct<char*>
#1  LogosAPI::getClient(QString const&, LogosTransportConfig const&)
#2  CoreManager::CoreManager(LogosAPI*)            // the LogosModules ctor

Independent of timing (deferring the construction past load doesn't help), delivery_module tag (v0.1.1 and v0.1.2 both crash), logos-module-builder rev, or SDK pin. The same binary runs fine on an older Basecamp build and under logoscore; it crashes on the current pre-release AppImage.

Root cause (already tracked upstream)

• Demo / clarify how a core module can consume delivery_module — current attempt SIGSEGVs in LogosAPI::getClient logos-delivery-module#31 — "how a core module can consume delivery_module — current attempt SIGSEGVs in LogosAPI::getClient" (identical stack). Maintainer: "we'll check the story of 'core' module using delivery. This must work."
• Third-party core plugins have no token bootstrap path — cannot call other modules via IPC logos-basecamp#150 — third-party core plugins have no token-bootstrap path for cross-module IPC.

logos-delivery-demo works precisely because it's a ui_qml module with a C++ backend (runs in ui-host, where getClient works), not a core module.

Ask

tutorial-v3 should either:

1. add a core + delivery_module example once feat: update tutorial to guide user to write mcp server tests #31 is fixed, or
2. explicitly call out — in the Part 1/Part 2 "core + QML UI" sections — that consuming delivery_module (and, per #150, likely any third-party-plugin → other-module IPC) must currently be done from a ui_qml C++ backend, pointing readers to logos-delivery-demo and feat: update tutorial to guide user to write mcp server tests #31/#150.

Hit while building a real module (decentralized audio broadcast + Waku/LogosMessaging discovery). Happy to share the repro repo if useful.