C0b: wire Critic + Delivery into run.Executor

Continues finishing the executor's run.Ports wiring (after C0's Palette).

Critic (run/critic.go): when Ports.Critic is set and the agent enables it, the
executor calls Monitor at run start, feeds RecordStep/RecordToolStart from the
step observer, drains the critic's Steer messages into the loop via
agent.WithSteer, and binds the run's hard cancellation to the critic's
(extendable) Deadline through a watch goroutine — a healthy-but-slow run gets
room while a hung one is killed. Stop() on run end. Soft timeout from
Defaults.CriticSoftTimeout (default 90s). nil-safe: no critic / not-enabled =
no-op.

Delivery (run/executor.go deliver): after the run, when Ports.Delivery is set
and inv.DeliveryID is non-empty, the executor posts Result.Output (or
DeliverError on failure) to a host-interpreted deliver.Target
{inv.DeliveryKind, inv.DeliveryID}. Empty target = caller reads Result.Output
itself (the synchronous default; the `.agent run` canary). Best-effort +
detached.

tool.Invocation gains DeliveryKind/DeliveryID (host-set egress target).

Tests: critic monitored/fed/steered/stopped when enabled, untouched when not;
delivery posts on a target, skips without one. Deferred: Checkpointer (needs a
majordomo hook to snapshot the running message history).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

tool/registry.go

@@ -173,6 +173,13 @@ type Invocation struct {
 	CallerID  string
 	ChannelID string
 	GuildID   string
+	// DeliveryKind / DeliveryID name where the executor posts the run's output
+	// via run.Ports.Delivery — a host-interpreted Target ("channel"/"dm"/
+	// "thread"/...). An empty DeliveryID means the executor delivers nothing
+	// and the caller reads Result.Output itself (the synchronous default; the
+	// `.agent run` canary works this way).
+	DeliveryKind string
+	DeliveryID   string
 	// CallerIsAdmin is true when the caller is a mort admin (Member.Admin).
 	// Populated by the executor at run dispatch via Bot.GetMember; defaults
 	// to false on any lookup failure (member not found, DB error, empty