P4: persona noun — Agent + ToRunnable bridge + Memory store

The headline P4 piece (clean redesign): the Agent persona noun, decoupled from
its Discord shell.
- agent.go/storage.go/builtin_loader.go moved from mort's pkg/logic/agents; the
  Storage seam drops the Discord CommandBindingStorage embedding (a host
  concern). The host-entangled files (commands, chatbot_provider, command-
  binding dispatcher, personalization, system) stay in mort.
- runnable.go: Agent.ToRunnable() lowers a persona into run.RunnableAgent — the
  bridge that lets run.Executor run a persona without importing this battery
  (the inversion of agentexec.Run(*agents.Agent)).
- memory.go: NewMemory() — zero-dep in-process persona Storage (all 11 CRUD +
  trigger-query methods).

Tests: ToRunnable field/phase mapping; Memory round-trip. CI invariant: core
imports ZERO from persona.

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

persona/runnable.go

@@ -0,0 +1,37 @@
+package persona
+
+import "gitea.stevedudenhoeffer.com/steve/executus/run"
+
+// ToRunnable lowers an Agent persona into the kernel's run.RunnableAgent DTO —
+// the bridge that lets run.Executor run a persona WITHOUT importing this
+// battery (the inversion of mort's agentexec.Run(*agents.Agent)). It maps the
+// static shape only; per-run personalization, palette resolution, the critic,
+// audit, etc. are supplied separately via run.Ports.
+func (a *Agent) ToRunnable() run.RunnableAgent {
+	ra := run.RunnableAgent{
+		ID:              a.ID,
+		Name:            a.Name,
+		SystemPrompt:    a.SystemPrompt,
+		ModelTier:       a.ModelTier,
+		MaxIterations:   a.MaxIterations,
+		MaxRuntime:      a.MaxRuntime,
+		LowLevelTools:   a.LowLevelTools,
+		SkillPalette:    a.SkillPalette,
+		SubAgentPalette: a.SubAgentPalette,
+		Critic: run.CriticConfig{
+			Enabled:            a.CriticEnabled,
+			BackstopMultiplier: a.CriticBackstopMultiplier,
+		},
+	}
+	for _, p := range a.Phases {
+		ra.Phases = append(ra.Phases, run.Phase{
+			Name:          p.Name,
+			SystemPrompt:  p.SystemPrompt,
+			ModelTier:     p.ModelTier,
+			MaxIterations: p.MaxIter,
+			Tools:         p.Tools,
+			Optional:      p.Optional,
+		})
+	}
+	return ra
+}