docs: plan backend foundation phase

.planning/phases/001-go-backend-foundation-and-workflow-boundary/001-RESEARCH.md

@@ -0,0 +1,69 @@
+# Phase 1 Research
+
+## Question
+
+How should the first Go backend scaffold be shaped so it can internalize
+`agent-farm-go` workflow patterns without overbuilding?
+
+## Findings
+
+### Keep the first backend narrow
+
+Phase 1 should prove structure, contracts, and validation, not product behavior.
+The safest first slice is:
+
+- `cmd/tutor-api` entrypoint
+- internal config package
+- internal HTTP/app package
+- internal workflow contract package
+- small health or version endpoint
+- tests for config and workflow boundary behavior
+
+### Prefer typed interfaces over runtime coupling
+
+The backend should expose a `WorkflowRunner` style interface that future phases
+can implement using internalized `agent-farm-go` execution. Phase 1 can use
+stub/no-op implementations as long as the interface boundaries and contracts are
+clear.
+
+### Avoid premature infrastructure
+
+Do not add Postgres, migrations, queues, auth, frontend, or image generation in
+Phase 1. Those are real needs later, but adding them before the backend boundary
+exists would violate KISS/YAGNI.
+
+### Module boundary recommendation
+
+Initial Go package boundaries:
+
+- `internal/app`: service assembly and dependency wiring
+- `internal/config`: environment/runtime config
+- `internal/httpapi`: HTTP routing and handlers
+- `internal/workflows`: workflow interfaces and typed contracts
+- `internal/version`: version/build metadata if needed
+
+Future packages can be added when their phase arrives:
+
+- `internal/interview`
+- `internal/learner_memory`
+- `internal/progression`
+- `internal/ontology`
+- `internal/assets`
+
+## Risks
+
+- Making workflow interfaces too generic creates a framework before use.
+- Putting typed contracts in HTTP handlers will make future phases hard to
+  isolate.
+- Shelling out from handlers would contradict the internalized workflow decision.
+
+## Recommendation
+
+Plan Phase 1 as a scaffold and boundary proof:
+
+1. Create Go module and package skeleton.
+2. Add config for app address and workflow runtime keys.
+3. Add typed workflow contracts from the planning document in minimal Go form.
+4. Add a stub workflow runner.
+5. Add health endpoint and tests.
+6. Document build/test commands in `AGENTS.md`.