Reflect on entering Review and ground the next coach

The controller fetches a reflection asynchronously on enterReview
(generation-guarded, non-blocking, graceful) and caches a one-line
recap plus a latest-wins carry-forward. The recap projects onto Review,
the carry-forward onto the next Planning, and both ride the snapshot.
RequestCoach composes the carry-forward into the coach's existing
free-form grounding string, so ai.Coach is unchanged.

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

internal/store/store.go

@@ -21,6 +21,10 @@ type Snapshot struct {
 	OutcomePending   string              `json:"outcome_pending,omitempty"`
 
 	AllowedWindowClasses []string `json:"allowed_window_classes,omitempty"`
+
+	ReflectionStatus string `json:"reflection_status,omitempty"`
+	ReflectionRecap  string `json:"reflection_recap,omitempty"`
+	CarryForward     string `json:"carry_forward,omitempty"`
 }
 
 // DefaultPath returns ~/.antidrift/state.json.