Runtime trait surface

The minimal trait pair (canopen-eds-rt (BB_0084)) the generated devices implement and any downstream CAN adapter consumes. Lives in a tiny canopen-eds-rt crate so the runtime contract is not coupled to either the codegen or the connector.

Feature: Runtime trait surface FEAT_0065
status: open
satisfies: FEAT_0060
is satisfied by: REQ_0750, REQ_0751, REQ_0752, REQ_0753, REQ_0754, REQ_0755, REQ_0756
is refined by: QG_0017, CON_0023, ADR_0084, ADR_0085
is implemented by: BB_0084

The minimal trait pair the generated devices implement and any downstream CAN adapter consumes. Lives in a tiny canopen-eds-rt crate so the runtime contract is not coupled to either the codegen or the connector.
Requirement: CanOpenDevice trait shape REQ_0750
status: open
satisfies: FEAT_0065
is verified by: TEST_0640

The crate shall define a CanOpenDevice trait with const IDENTITY: Identity, fn node_id(&self) -> u8, fn set_node_id(&mut self, id: u8), fn nmt_state(&self) -> NmtState, fn set_nmt_state(&mut self, s: NmtState), fn on_rpdo(&mut self, idx: u8, frame: PdoFrame<'_>) -> Result<(), CanOpenError>, and fn drain_tpdos(&mut self, out: &mut dyn TpdoSink) -> Result<(), CanOpenError>. The trait shall add no async methods on the RPDO/TPDO path — the frame-handling hot path stays synchronous.
Requirement: CanOpenConfigurable trait shape for bring-up REQ_0751
status: open
satisfies: FEAT_0065
is verified by: TEST_0641

The crate shall define CanOpenConfigurable: CanOpenDevice carrying async fn configure<S: SdoClient>(&mut self, sdo: &mut S) -> Result<(), CanOpenError>. Bring-up SDO writes (PDO comm, PDO mapping, optional NMT start) live inside the generated body of this method.
Requirement: Traits live in canopen-eds-rt, not taktora-connector-can REQ_0752
status: open
satisfies: FEAT_0065
is verified by: TEST_0642

CanOpenDevice and CanOpenConfigurable shall live in a dedicated canopen-eds-rt crate. They shall not live in taktora-connector-can, fieldbus-od-core, or any other taktora-internal crate. Any CAN consumer shall be able to adopt the generated drivers without depending on taktora.
Requirement: Frame payloads use heapless::Vec<u8, 8> REQ_0753
status: open
satisfies: FEAT_0065
is verified by: TEST_0643
links incoming: RISK_0023

PdoFrame shall borrow an inbound payload as &[u8]; PdoOut shall carry the outbound payload as heapless::Vec<u8, 8> (classical CAN cap). PdoOut::can_id: u32 shall carry the resolved COB-ID computed by generated code from the current node_id() and the EDS-declared base COB-ID; the consumer forwards it as the CAN frame ID without further resolution. CAN-FD payloads are out of scope this round (see NO CAN-FD payload support i... (REQ_0791)).
Requirement: Frame-per-PDO dispatch shape REQ_0754
status: open
satisfies: FEAT_0065
is verified by: TEST_0640

on_rpdo(idx, frame) shall accept an RPDO enumeration index in 0..=3 (CANopen’s 4-RPDO cap from CiA 301) and route to the right typed decoder in generated code. Caller-side resolution from CAN ID to RPDO enumeration uses the configured 0x1400..0x14FF communication parameters and is the consumer’s responsibility. drain_tpdos(out) shall produce zero or more frames per call into a caller-provided TpdoSink.
Requirement: CanOpenError variant surface REQ_0755
status: open
satisfies: FEAT_0065
is verified by: TEST_0640

CanOpenError shall enumerate CiA 301 SDO abort codes (AbortCode(u32)), payload-length mismatch (PdoLenMismatch { expected: u8, got: u8 }), unknown-index, NmtStateViolation, and a TransportFailed(&'static str) variant for caller-supplied I/O failures.
Requirement: RPDO rejected outside Operational state REQ_0756
status: open
satisfies: FEAT_0065
is verified by: TEST_0644

Generated code shall reject on_rpdo calls when nmt_state() != NmtState::Operational, returning CanOpenError::NmtStateViolation. NMT state is caller-managed; the trait carries getter / setter but no transition methods.