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

compose/oikos/Dockerfile

@@ -0,0 +1,21 @@
+# Multi-stage Dockerfile for Oikos (ADR 0001: single binary)
+FROM golang:1.26-alpine AS builder
+
+RUN apk add --no-cache git ca-certificates
+
+WORKDIR /build
+COPY go.mod go.sum ./
+RUN go mod download
+
+COPY . .
+
+RUN CGO_ENABLED=0 go build -o /oikos -tags timetzdata -ldflags="-s -w" ./cmd/oikos
+
+# --- Runtime: distroless static ---
+FROM gcr.io/distroless/static:nonroot
+
+COPY --from=builder /oikos /oikos
+COPY --from=builder /build/seeds /seeds
+COPY --from=builder /build/migrations /migrations
+
+ENTRYPOINT ["/oikos"]