Add the foundational types for ADR-049 streaming handlers:
- StreamingHandler, ResponseStream type aliases and HandlerKind enum
(Once | Stream) in registration.rs, with make_streaming_handler() helper
- CallError::invalid_operation_type() in wire.rs (sixth protocol code,
retryable: false)
- HandlerRegistration.handler flipped from Handler to HandlerKind;
HandlerRegistration::new() now takes HandlerKind
- OperationRegistryBuilder absorbs wrapping: with_local/with_leaf/
with_leaf_provenance wrap raw Handler in HandlerKind::Once for
Query/Mutation; new with_local_streaming/with_leaf_streaming take a
StreamingHandler and wrap in HandlerKind::Stream for Subscription.
Builder validates kind matches spec.op_type (mismatch = startup error)
- OperationRegistry::register() returns Result<(), String> with a clear
mismatch message; all call sites updated to handle the Result
- invoke() matches on HandlerKind: Once -> existing path; Stream ->
INVALID_OPERATION_TYPE error envelope (guards against silent
truncation; invoke_streaming() added in a downstream task)
- OverlayOperationEnv::invoke_with_policy matches on HandlerKind:
Once -> dispatch; Stream -> INVALID_OPERATION_TYPE (composition is
request/response-only)
- Migrated every HandlerRegistration::new() construction site (~95)
to wrap raw Handler in HandlerKind::Once(handler); the builder sites
are handled by the builder-absorbs-wrapping change
- Updated two websocket subscription tests that relied on Subscription
ops dispatching via invoke() to expect INVALID_OPERATION_TYPE
- Added unit tests for invoke/register validation and
make_streaming_handler
Enforce AccessControl on overlay ops in OverlayOperationEnv::invoke_with_policy
(alknet-call) so the hub's calls to browser-registered ops are gated by the
browser's AccessControl — matching OperationRegistry::invoke semantics for
internal composition (caller identity = parent handler_identity.as_identity()).
Add src/websocket/overlay.rs with 19 integration tests covering the connection-
local overlay acceptance criteria: browser ops land in the per-CallConnection
overlay (not PeerCompositeEnv), no PeerId for the browser, register_imported()/
register_imported_all() populate the overlay, hub outgoing calls route through
overlay_env() (not PeerRef::Specific), PeerRef::Specific('browser-X') routes to
NOT_FOUND, AccessControl gates hub calls (allowed/forbidden/default), overlay is
per-connection isolated and dropped on WS close, WS close aborts in-flight calls
with ADR-016 cascade, bidirectionality, and browser-with-no-ops use-case scoping.
