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.

plans/2026-08-15-hexagonal-architecture.md

@@ -1,7 +1,7 @@
 # Hexagonal architecture for Oikos — design and phased refactor plan
 
 **Date:** 2026-08-15
-**Status:** In progress — Phase 0 shipped; Phases 1–9 pending
+**Status:** In progress — Phases 0–2 shipped; Phases 3–9 pending
 **Scope:** All Go code (`cmd/oikos`, `cmd/nomos`, `cmd/webhook`) and the UI
 split. One hexagon covers the oikos backend; nomos is an external agent
 client that gets an internal cleanup (Phase 8) but stays outside the core.

plans/index.md

@@ -22,7 +22,7 @@ went sideways, open an investigation.
 | 2026-08-04 | [Hermes MCP client integration](done/2026-08-04-hermes-mcp-client-integration.md) | Done — deployed |
 | 2026-08-05 | [Agent execution safety: QEMU guest agent gate + host-mutation guard](done/2026-08-05-agent-execution-safety-qemu-guest-agent-gate.md) | Done — implemented (1b9c761) |
 | 2026-08-05 | [Backend evaluation: architecture, security, and reliability improvements](2026-08-05-backend-evaluation-improvements.md) | Done — all three phases (B, D, E) implemented as code (0.28.0–0.29.0), deployed, and hardened via review. Remaining: C (security) and F (performance) backlog. |
-| 2026-08-15 | [Hexagonal architecture — design and phased refactor](2026-08-15-hexagonal-architecture.md) | In Progress — Phase 0 done (ADR 0016, core scaffold, domain moved, depguard) |
+| 2026-08-15 | [Hexagonal architecture — design and phased refactor](2026-08-15-hexagonal-architecture.md) | In Progress — Phases 0–2 done (ADR 0016, client extracted to dtoro/oikos-web, ports + adapters scaffold); Phase 3 next |
 
 ## Done