Branching zones G8d: Manor Blackspire stacked 3-way forks (hub style)

T3 zone, fourth authored graph. Shape: two stacked 3-way forks
(great_hall, upper_hall). The player picks twice in a row from a
wide menu — distinct from the binary forks in G8a/b and the parallel
Y-trees in G8c.

Completes lock-kind coverage by G8d: this is the first authored use of
LockLevelMin (tower_observatory gated at L7). With Perception (DC 14
study, DC 15 hidden_oratory), StatCheck INT (library), and LockNone,
all four non-trivial lock kinds now appear in shipping zones.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

internal/plugin/zone_graph_manor_blackspire_test.go

@@ -0,0 +1,71 @@
+package plugin
+
+import "testing"
+
+func TestManorBlackspireGraph_Registered(t *testing.T) {
+	g, ok := zoneGraphRegistry[ZoneManorBlackspire]
+	if !ok {
+		t.Fatal("zoneManorBlackspireGraph not registered")
+	}
+	if g.Entry != "manor_blackspire.entry" {
+		t.Errorf("entry node = %q", g.Entry)
+	}
+	if len(g.Nodes) != 11 {
+		t.Errorf("nodes = %d, want 11", len(g.Nodes))
+	}
+}
+
+// TestManorBlackspireGraph_TwoStackedThreeWayForks captures the design
+// shape: both great_hall and upper_hall expose three options.
+func TestManorBlackspireGraph_TwoStackedThreeWayForks(t *testing.T) {
+	g := zoneManorBlackspireGraph()
+	for _, hub := range []string{
+		"manor_blackspire.great_hall",
+		"manor_blackspire.upper_hall",
+	} {
+		outs := g.outgoingEdges(hub)
+		if len(outs) != 3 {
+			t.Errorf("%s outgoing = %d, want 3", hub, len(outs))
+		}
+	}
+}
+
+func TestManorBlackspireGraph_AllSpokesReachBoss(t *testing.T) {
+	g := zoneManorBlackspireGraph()
+	for _, leaf := range []string{
+		"manor_blackspire.master_bedroom",
+		"manor_blackspire.tower_observatory",
+		"manor_blackspire.hidden_oratory",
+		"manor_blackspire.portrait_gallery",
+		"manor_blackspire.study",
+		"manor_blackspire.library",
+	} {
+		if !reachable(g, leaf, "manor_blackspire.boss") {
+			t.Errorf("%s unreachable to boss", leaf)
+		}
+	}
+}
+
+// TestManorBlackspireGraph_LockLevelMinFirstUse verifies this zone is
+// the first to author LockLevelMin, completing lock-kind coverage
+// (Perception, StatCheck, LevelMin, LockNone) by G8d.
+func TestManorBlackspireGraph_LockLevelMinFirstUse(t *testing.T) {
+	g := zoneManorBlackspireGraph()
+	var levelMinEdge *ZoneEdge
+	for _, outs := range g.Edges {
+		for i := range outs {
+			if outs[i].Lock == LockLevelMin {
+				levelMinEdge = &outs[i]
+			}
+		}
+	}
+	if levelMinEdge == nil {
+		t.Fatal("expected at least one LockLevelMin edge")
+	}
+	if min := lockDataInt(levelMinEdge.LockData, "min_level", 0); min < 7 {
+		t.Errorf("min_level = %d, want >= 7 (T3 zone)", min)
+	}
+	if levelMinEdge.Hint == "" {
+		t.Error("level-gated edge missing hint")
+	}
+}