phase 1: Go foundation — module, migrations, domain, seed ingest

Core deliverables:
- Go module github.com/dtoro/oikos (Go 1.26.3)
- cmd/oikos: single binary with role subcommands (migrate, seed, export)
- 6 SQL migrations: ontology meta-schema, entity instances (UUID+slug,
  blast_radius recursive function), operations (signals/checks/approvals),
  cognition (classifications/executions/feedback/patterns/skills), policy,
  observability (TimescaleDB hypertables + CAGGs + retention)
- Domain layer: entity, signal, execution, classification, pattern, skill,
  approval, check types + 11 sentinel errors + lifecycle state machines
- DB layer: pgx pool, SQL splitter (handles 94436 and -- comments), migration
  runner, seed ingest (ontology+inventory+policy) with content-hash dedup
- Config: env-based with defaults, secrets redaction
- Observability: slog JSON logger with debug mode
- Infrastructure: Makefile, docker-compose.yml, multi-stage Dockerfile
  (distroless, CGO_ENABLED=0)

Verified end-to-end against timescale/timescaledb:2.17.2-pg16:
- 6 migrations applied (65 SQL statements)
- Seeds ingested: 6 lifecycles, 59 entity types, 46 relationship types,
  111 entities, 144 relationships, 4 risk classes, 27 approval rules,
  9 autonomy settings
- Idempotent: second seed run is a no-op (content hash matches)

Bugs fixed during implementation:
- TimescaleDB CAGGs can't run in a transaction -> splitSQL() executes
  statements individually
- Semicolons in -- comments treated as separators -> comment handling
- YAML keys source/target didn't match code's source_type/target_type
- yaml.Marshal produced YAML for JSONB columns -> json.Marshal

Makefile

@@ -0,0 +1,36 @@
+.PHONY: build test lint generate dev migrate seed export clean
+
+BINARY := oikos
+GO := /opt/homebrew/bin/go
+
+build:
+	$(GO) build -o $(BINARY) -tags timetzdata ./cmd/oikos
+
+test:
+	$(GO) test -race -cover ./...
+
+lint:
+	$(GO) vet ./...
+	@command -v golangci-lint >/dev/null 2>&1 && golangci-lint run || echo "golangci-lint not installed, skipping"
+
+generate:
+	@echo "TODO: oapi-codegen + sqlc generation"
+
+migrate:
+	$(GO) run ./cmd/oikos migrate
+
+seed:
+	$(GO) run ./cmd/oikos seed
+
+export:
+	$(GO) run ./cmd/oikos export
+
+dev:
+	docker compose --profile dev up -d
+
+clean:
+	rm -f $(BINARY)
+	$(GO) clean -testcache
+
+tidy:
+	$(GO) mod tidy