P0: Effect 4 migration left the engine unable to run any workflow

[roninjin10]

The Effect 4 migration (d9c9676938 → 0abdf1e014) landed main in a state where the engine cannot execute a workflow at all. Three distinct breakages; the first two are fixed on main, the third is open.

Fixed on main

1. Committed merge-conflict markers — packages/engine/src/engine.js shipped an unresolved conflict block, making the module a syntax error (Unexpected <<). Every smithers command and every engine import died. Fixed in 6cd0020d03.
2. Effect.either removed in Effect 4 — 11 source call sites plus 2 test call sites survived the migration (packages/engine/src/events.js, packages/engine/src/hot/{overlay,HotWorkflowController}.js, packages/sandbox/src/sandboxPath.js, apps/cli/src/{index,supervisor}.js). Every workflow render failed with Effect.either is not a function. Fixed in aaadd41d0d by porting to Effect.result ("Left"/"Right" → "Failure"/"Success", .left/.right → .failure/.success).

Still open

3. packages/engine/src/effect/workflow-make-bridge.js is written against the Effect 3 workflow API. Reproduce with any workflow:

bun apps/cli/src/index.js up .smithers/workflows/hello.tsx --input '{}'
# RUN_FAILED: run workflow: undefined is not an object (evaluating 'options.payload')

• Workflow.make is now make(tag, options), not make({ name, payload, ... }). Passing the tag positionally gets past this error.
• The next failure is WorkflowInstance.initial is not a function — WorkflowEngine.WorkflowInstance.initial(workflowBridge, runId) no longer exists in effect@4.0.0-beta.102.

There are likely more sites past that point; the bridge needs a real port rather than incremental patches, which is why it is not included in the two fixes above.

Impact

While (3) is open, main cannot run a single workflow — no up, no oneshot, no monitor, no e2e. Any CI job that executes a workflow is red.

[roninjin10]

Resolved on current main. Commit 0139ef8 restored the Effect 4 Workflow.make(tag, options) signature, and the dependency alignment in cafd2ad moved the repo to effect@4.0.0-beta.105, where WorkflowEngine.WorkflowInstance.initial is present again. Verified from source at a28bd72: pnpm -C packages/engine exec bun test tests/workflow-bridge-static.test.js tests/workflow-make-bridge-internals.test.js passes 7/7, including a bridge-managed workflow execution without the legacy executor.