- adds ErrorType constants for rejected-by-application, DNS resolution failed,
port not allowed, invalid link destination, and resources not available
- adds corresponding CircuitFailureCause strings reported in circuit events
- extracts classifyDialError() in route handler to map dial errors to specific
error codes using typed errors, syscall constants, and string matching
- detects DNS errors via *net.DNSError and string fallback for ER/T hosted
services where errors are serialized through the SDK message protocol
- detects resource exhaustion via EMFILE, ENFILE, ENOBUFS syscall errors
- introduces InvalidLinkDestinationError typed error in forwarder package
- adds unit tests covering all 16 classification cases
- adds integration tests for rejected-by-application (SDK host),
DNS resolution failed, connection refused, and port not allowed
(ER/T host mode) with circuit event verification
- adds CreateEnrollAndStartTunnelerEdgeRouterWithCfgTweaks to test context
- adds CreateCircuitV3 message type and handler for routers that have
already authorized dials locally via RDM, bypassing service session
tokens in favor of identity ID, service ID, and pre-assigned circuit ID
- renames CreateCircuitRequest/Response to CreateCircuitV2Request/V2Response
for clarity now that V3 exists
- adds CircuitManager.Reserve to atomically claim circuit IDs before routing,
preventing collisions on pre-assigned IDs
- extends CreateCircuitParams with GetCircuitId so V3 can supply a
pre-assigned circuit ID (falls back to UUID generation when empty)
- fixes IsDialableByIdentity which was incorrectly calling IsBindableByIdentity
- extracts V2 handler into its own file create_circuit_v2.go
- adds CreateCircuitV3RequestType/ResponseType (20222/20223) to edge_ctrl protobuf
- registers V3 handler in controller server
Paul Lorenz