feat(hiroz): graph-settle wait + service-schema discovery (hu stack 3/9)

[YuanYuYuan]

Summary

Stacked PR 3 of 9 (#231 split). Core-library primitives the hu plugin host builds on:

• Graph::has_external_entity / wait_for_external_settled: wait for a genuinely external participant then graph-quiet, so one-shot introspection can replace blind sleeps with a real condition.
• ZNode::discover_service_schema: resolve a service's request/response type names from the graph.
• parameter wire-types + service tweaks and an ffi/service.rs adjustment; demo client updated to the refined API.

Base: dev/pr-hu-1b-logger-msgs.

Breaking Changes

ZNode::create_service now additionally requires T::Request: WithTypeInfo and T::Response: WithTypeInfo (to auto-register the service schema for discovery). Downstream callers whose request/response types implement ServiceTypeInfo but not MessageTypeInfo will need to add it. In practice all generated hiroz message types already implement it. (Correcting the initial 'none' — thanks to the Copilot review for catching this.)

[Copilot]

Pull request overview

Adds new graph and schema-discovery primitives that enable one-shot tooling (notably the hu plugin host) to replace fixed sleeps with condition-based waiting and to resolve service Request/Response schemas via live ~get_type_description queries. It also wires built-in parameter services into the type-description service so those schemas become discoverable.

Changes:

• Add Graph::has_external_entity and Graph::wait_for_external_settled to wait for a genuinely external participant and then graph quiet.
• Add ZNode::discover_service_schema and extend ZNode::create_service to auto-register Request/Response schemas with the node’s type-description service.
• Register rcl_interfaces parameter service Request/Response schemas at ParameterService startup when the type-description service is enabled, and refine FFI service client call reply handling.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
crates/hiroz/src/parameter/wire_types.rs	Adds explicit schema builders + registration for built-in parameter service wire types.
crates/hiroz/src/parameter/service.rs	Passes optional type-description service into ParameterService and registers parameter schemas on startup.
crates/hiroz/src/node.rs	Adds discover_service_schema and service-side schema auto-registration in create_service.
crates/hiroz/src/graph.rs	Adds external-participant detection and a two-phase “external then quiet” wait helper.
crates/hiroz/src/ffi/service.rs	Ensures per-call reply isolation for FFI service client calls and maps “no queryable matches” to timeout.
crates/hiroz/examples/demo_nodes/add_two_ints_client.rs	Increases demo client call timeout to accommodate longer discovery/interop latencies.

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[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

Comments suppressed due to low confidence (1)

crates/hiroz/src/graph.rs:567

• Phase 2 of wait_for_external_settled never re-checks that an external entity is still present. If an external participant briefly appears and then disappears before the graph goes quiet, this can still return true, contradicting the doc comment that the entity is still present and causing one-shot callers to proceed with an empty/self-only graph.

        loop {
            let notified = self.change_notify.notified();
            tokio::pin!(notified);
            let remaining = deadline.saturating_duration_since(tokio::time::Instant::now());
            if remaining.is_zero() {

[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.