feat: Phase 2 — ports package, secrets port move, postgres adapter move

Problem: the hexagon's Phase 2 (plans/2026-08-15-hexagonal-architecture.md)
must give the use-cases-to-be their contract surface: driven-port
interfaces, test fakes, the secrets interface moved into core, and the
postgres package inside the adapters tree — before the first vertical
slice (Phase 3) can wire a composition root.

Change:
- internal/core/ports: full driven-port catalog per plan §3.3 —
  repositories as transaction-scoped aggregates whose inputs carry
  derived checks, audit, and events (§3.6), plus CommandExecutor,
  TargetResolver, Checker, Secrets, EventPublisher, Provisioner.
  Port-local payload types (Event, AuditEntry, CheckDef, KnowledgeEntry,
  ExecResult) keep signatures off infrastructure; TypeTree aliases
  internal/ontology (pure over domain) until checkdefaults is absorbed.
  ReadModels intentionally not declared yet — it materializes with the
  Phase 3 slice and grows as report handlers rewire.
- secrets.Backend is now an alias of ports.Secrets; implementations
  (Infisical, SOPS, Manager) unchanged. mcp's local secretBackend
  subset is deleted; tool constructors take ports.Secrets.
- internal/db → internal/adapters/postgres (mechanical import rewrite;
  package identifier stays db until the Phase 3 repository split).
  sqlc.yaml, Makefile, golangci exclusions, and docs follow the move;
  make generate-check verified.
- internal/adapters/ssh: Executor implements ports.CommandExecutor over
  the actuator dial pool + RunStreaming (10-min default timeout carried
  over from the httpapi path).
- internal/adapters/remote: Resolver implements ports.TargetResolver
  delegating to internal/remote (still pool-based; drops onto
  ports.EntityRepository when repositories land in Phase 3 — documented
  transitional import).
- internal/core/ports/portstest: importable fakes — in-memory
  EntityRepo (with check-then-act SetState, side-effect recording),
  RecordingExecutor, FakeChecker, SpyPublisher; port-satisfaction
  guards; tests.

Risk: ports are declared ahead of implementations — signatures firm up
per phase as slices land (documented in the package doc); the
remote→postgres transitional import is explicit and dissolves in
Phase 3.

Verification: go vet, make test (race, 19 packages), generate-check,
golangci on core+adapters — 0 issues; full-repo baseline down
365→344.

internal/adapters/postgres/sqlcgen/relationships.sql.go

@@ -0,0 +1,177 @@
+// 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 insertRelationshipIfAbsent = `-- name: InsertRelationshipIfAbsent :execrows
+INSERT INTO relationships (source_id, target_id, type, attributes, valid_from)
+SELECT $1, $2, $3,
+       $4::jsonb, now()
+WHERE NOT EXISTS (
+    SELECT 1 FROM relationships
+    WHERE source_id = $1
+      AND target_id = $2
+      AND type = $3
+      AND valid_to IS NULL
+)
+`
+
+type InsertRelationshipIfAbsentParams struct {
+	SourceID   uuid.UUID
+	TargetID   uuid.UUID
+	Type       string
+	Attributes []byte
+}
+
+// Idempotent relationship insert (the create_relationship surface): no-op if
+// an active edge of the same source/target/type already exists. Replaces the
+// raw INSERT...WHERE NOT EXISTS used in entity_tools.go.
+func (q *Queries) InsertRelationshipIfAbsent(ctx context.Context, arg InsertRelationshipIfAbsentParams) (int64, error) {
+	result, err := q.db.Exec(ctx, insertRelationshipIfAbsent,
+		arg.SourceID,
+		arg.TargetID,
+		arg.Type,
+		arg.Attributes,
+	)
+	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
+}