phase 2 (part 2): sqlc queries, audit/event helpers, event NOTIFY trigger

- sqlc.yaml + internal/db/queries/*.sql: typed queries for entities,
  relationships, ontology, operations (signals, events, audit,
  idempotency, entity_status)
- internal/db/sqlcgen/: generated Go from sqlc (pgx/v5)
- internal/observability/record.go: Audit() and Event() helpers that
  write in the caller's transaction (SG10). actorLabel is interim text
  identity in detail JSON until OIDC resolution lands; actor_id column
  exists but is not yet populated
- migrations/008: post-commit pg_notify trigger on events table for
  SSE fan-out (SG8/SG10)

internal/db/sqlcgen/relationships.sql.go

@@ -0,0 +1,165 @@
+// Code generated by sqlc. DO NOT EDIT.
+// versions:
+//   sqlc v1.29.0
+// source: relationships.sql
+
+package sqlcgen
+
+import (
+	"context"
+	"time"
+
+	"github.com/google/uuid"
+)
+
+const endCurrentRelationship = `-- name: EndCurrentRelationship :execrows
+UPDATE relationships SET valid_to = now()
+WHERE source_id = $1 AND target_id = $2 AND type = $3 AND valid_to IS NULL
+`
+
+type EndCurrentRelationshipParams struct {
+	SourceID uuid.UUID
+	TargetID uuid.UUID
+	Type     string
+}
+
+func (q *Queries) EndCurrentRelationship(ctx context.Context, arg EndCurrentRelationshipParams) (int64, error) {
+	result, err := q.db.Exec(ctx, endCurrentRelationship, arg.SourceID, arg.TargetID, arg.Type)
+	if err != nil {
+		return 0, err
+	}
+	return result.RowsAffected(), nil
+}
+
+const listEntityRelations = `-- name: ListEntityRelations :many
+SELECT se.slug AS source_slug, te.slug AS target_slug, r.type, r.attributes,
+       r.valid_from, r.valid_to
+FROM relationships r
+JOIN entities se ON se.id = r.source_id
+JOIN entities te ON te.id = r.target_id
+WHERE r.valid_to IS NULL
+  AND (($1::text IN ('out','both') AND r.source_id = $2)
+    OR ($1::text IN ('in','both')  AND r.target_id = $2))
+  AND ($3::text IS NULL OR r.type = $3)
+ORDER BY r.type, se.slug, te.slug
+`
+
+type ListEntityRelationsParams struct {
+	Direction string
+	ID        uuid.UUID
+	RelType   *string
+}
+
+type ListEntityRelationsRow struct {
+	SourceSlug string
+	TargetSlug string
+	Type       string
+	Attributes []byte
+	ValidFrom  time.Time
+	ValidTo    *time.Time
+}
+
+func (q *Queries) ListEntityRelations(ctx context.Context, arg ListEntityRelationsParams) ([]ListEntityRelationsRow, error) {
+	rows, err := q.db.Query(ctx, listEntityRelations, arg.Direction, arg.ID, arg.RelType)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	var items []ListEntityRelationsRow
+	for rows.Next() {
+		var i ListEntityRelationsRow
+		if err := rows.Scan(
+			&i.SourceSlug,
+			&i.TargetSlug,
+			&i.Type,
+			&i.Attributes,
+			&i.ValidFrom,
+			&i.ValidTo,
+		); err != nil {
+			return nil, err
+		}
+		items = append(items, i)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+	return items, nil
+}
+
+const listGraphEdges = `-- name: ListGraphEdges :many
+SELECT se.slug AS source_slug, te.slug AS target_slug, r.type, r.attributes,
+       r.valid_from, r.valid_to
+FROM relationships r
+JOIN entities se ON se.id = r.source_id
+JOIN entities te ON te.id = r.target_id
+WHERE r.valid_to IS NULL
+  AND r.source_id = ANY($1::uuid[])
+  AND r.target_id = ANY($1::uuid[])
+  AND ($2::text[] IS NULL OR r.type = ANY($2::text[]))
+ORDER BY r.type, se.slug, te.slug
+`
+
+type ListGraphEdgesParams struct {
+	Ids      []uuid.UUID
+	RelTypes []string
+}
+
+type ListGraphEdgesRow struct {
+	SourceSlug string
+	TargetSlug string
+	Type       string
+	Attributes []byte
+	ValidFrom  time.Time
+	ValidTo    *time.Time
+}
+
+func (q *Queries) ListGraphEdges(ctx context.Context, arg ListGraphEdgesParams) ([]ListGraphEdgesRow, error) {
+	rows, err := q.db.Query(ctx, listGraphEdges, arg.Ids, arg.RelTypes)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	var items []ListGraphEdgesRow
+	for rows.Next() {
+		var i ListGraphEdgesRow
+		if err := rows.Scan(
+			&i.SourceSlug,
+			&i.TargetSlug,
+			&i.Type,
+			&i.Attributes,
+			&i.ValidFrom,
+			&i.ValidTo,
+		); err != nil {
+			return nil, err
+		}
+		items = append(items, i)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+	return items, nil
+}
+
+const upsertCurrentRelationship = `-- name: UpsertCurrentRelationship :exec
+INSERT INTO relationships (source_id, target_id, type, attributes, valid_from, valid_to)
+VALUES ($1, $2, $3, $4, now(), NULL)
+ON CONFLICT (source_id, target_id, type) WHERE valid_to IS NULL
+DO UPDATE SET attributes = EXCLUDED.attributes
+`
+
+type UpsertCurrentRelationshipParams struct {
+	SourceID   uuid.UUID
+	TargetID   uuid.UUID
+	Type       string
+	Attributes []byte
+}
+
+func (q *Queries) UpsertCurrentRelationship(ctx context.Context, arg UpsertCurrentRelationshipParams) error {
+	_, err := q.db.Exec(ctx, upsertCurrentRelationship,
+		arg.SourceID,
+		arg.TargetID,
+		arg.Type,
+		arg.Attributes,
+	)
+	return err
+}