fix(rivetkit): detect unsupported inspector workflows

[jog1t]

Summary

• report inspector workflows as unsupported when no history callback is registered
• keep supported workflows with empty history distinct from unsupported workflows
• align native and WASM behavior
• add unit and cross-runtime WebSocket regression coverage

Verification

• git diff --check
• npx --yes @biomejs/biome@2.3.0 check rivetkit-typescript/packages/rivetkit/tests/driver/actor-inspector.test.ts (passes with one pre-existing non-null assertion warning)

Rust and driver tests were not run because the orb does not have Rust or workspace dependencies installed.

[claude]

Review

Solid, well-scoped fix. The core disambiguation logic (workflow_dispatch_result / is_dropped_reply_error in dispatch.rs, plus Reply<T>'s Drop impl that auto-sends actor/dropped_reply) already existed; this PR correctly wires the NAPI and wasm adapters to participate in it by dropping the reply when no get_workflow_history/replay_workflow callback is registered, instead of sending Ok(None) (which was indistinguishable from "callback exists but returned no history"). The flow through to inspector_ws.rs/inspector.rs (isWorkflowEnabled) is consistent end-to-end.

Correctness

• NAPI and wasm changes are symmetric, both now drop(reply) in the no-callback branch, matching the #[must_use = "... or dropping it sends actor/dropped_reply"] convention already established elsewhere in this codebase (event.rs). No leftover reachable code path sends Ok(None) for the unsupported case anymore.
• The wasm change correctly hoists the let Some(callback) = ... else { drop(reply); return; } check outside the async move block, so the borrow of callbacks and the early-return both happen before entering the callback-invocation future. No behavior change for the callback-present path.
• The updated NAPI test (workflow_requests_without_callbacks_drop_replies) correctly asserts on group()/code() == "actor"/"dropped_reply" rather than a magic string, matching how RivetTransportError::extract is used elsewhere in the same file.

Test coverage

• The new driver test exercises both the WebSocket Init message and a live WorkflowReplayRequest/WorkflowReplayResponse round trip for a non-workflow actor, complementing the existing HTTP /inspector/workflow-history coverage (which already asserted isWorkflowEnabled === false for the counter actor). Since it's registered under describeDriverMatrix, it runs against both native (NAPI) and wasm drivers, satisfying the "cross-runtime" claim in the PR description without a separate wasm-only test file.
• One gap: there's no new test asserting the positive case for WorkflowReplayResponse over the websocket specifically (isWorkflowEnabled === true when a callback is registered but returns no history for a given entryId). Existing HTTP-path tests around lines 738/784 likely already exercise the callback-present branch, but a websocket-level assertion would close the loop symmetrically with the new negative test.

Style

• Minor/non-blocking: drop(reply); immediately before return; is redundant (the Reply<T> would be dropped on scope exit regardless), but it's harmless and arguably clarifies intent alongside the accompanying comment.

Nothing blocking. Nice job aligning the two adapter layers with the pre-existing core semantics.

[jog1t]

Addressed the review in bc25e85:

• missing workflow replay callbacks now drop the reply in both NAPI and WASM, so replay responses report isWorkflowEnabled: false
• updated the NAPI unit test to cover dropped history and replay replies
• extended the cross-runtime WebSocket test to assert WorkflowReplayResponse
• Rust formatting was already fixed in cead2c1; Rustfmt CI passes

Validation: focused NAPI unit test passed; formatting and pre-commit hooks passed.

[railway-app]

🚅 Deployed to the rivet-pr-5455 environment in rivet-frontend

Service	Status	Web	Updated (UTC)
website	😴 Sleeping (View Logs)	Web	Jul 21, 2026 at 1:08 am
frontend-cloud	😴 Sleeping (View Logs)	Web	Jul 21, 2026 at 1:08 am
frontend-inspector	😴 Sleeping (View Logs)	Web	Jul 21, 2026 at 1:06 am
kitchen-sink	😴 Sleeping (View Logs)	Web	Jul 21, 2026 at 1:05 am
ladle	✅ Success (View Logs)	Web	Jul 20, 2026 at 10:32 pm
mcp-hub	✅ Success (View Logs)	Web	Jul 20, 2026 at 10:30 pm