merge: local_dev I2 evidence + gate U9 at auto_read

Bring I2 rollout reports onto the U9–U12 branch; keep FEATURE-MATRIX
out of this merge (managed via docs apply on local_dev). Tighten
ActiveSegmentProposer to PlanTier ≥ auto_read per Track I3.

internal/app/intentflow/turn.go

@@ -48,7 +48,8 @@ func (p *Plans) handleTurnElevated(ctx context.Context, in TurnInput) (*TurnResu
 	}
 
 	var proposal *intent.PlanProposal
-	if flags.U9Segment && !RulesCanDecide(text) && tier.Allows(TierShadow) {
+	// U9 live segment proposals require elevated tier ≥ auto_read (plan Track I3).
+	if flags.U9Segment && !RulesCanDecide(text) && tier.Allows(TierAutoRead) {
 		sp, propErr := ActiveSegmentProposer().Propose(ctx, SegmentProposalRequest{
 			Text:          text,
 			RequestDigest: digest,