Branching zones G8b: Forest of Shadows asymmetric fork + stat-check secret

T2 zone, second authored graph. Deliberately diverges from the diamond
shape so the !zone map renders distinctly:

- Asymmetric main fork: long branch (grove_descent → dryad_circle elite,
  2 mid-nodes) vs. short branch (thorn_tunnel, 1 mid-node, Perception
  DC 13 hint). Tests lock in the asymmetry.
- Pre-boss fork to a sapling_shrine secret behind LockStatCheck WIS
  DC 14 (LootBias 2.0). First authored zone exercising stat_check —
  Crypt's secret was Perception, so this validates the second lock kind
  end-to-end.

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

internal/plugin/zone_graph_forest_shadows.go

@@ -0,0 +1,69 @@
+package plugin
+
+// Phase G8b — Forest of Shadows branching graph.
+//
+// T2 zone. Per plan §G8 ("two forks for T2+") and the G8 design
+// session: deliberately a different shape from the Crypt diamond.
+//
+// Shape: asymmetric main fork + WIS-gated secret pre-boss.
+//
+//   entry → twisted_path → fork1
+//                            ├─[unlocked, w=1]── grove_descent → dryad_circle (elite) ─┐
+//                            │                                                          ├── fork2
+//                            └─[Perception DC 13, w=2]── thorn_tunnel ──────────────────┘
+//                                                                                      │
+//                                              ┌─[unlocked, w=1]── boss ────────────────┘
+//                                              │
+//                                              └─[WIS DC 14, w=2]── sapling_shrine (secret) → boss
+//
+// Asymmetry: long branch is two mid-nodes (grove_descent → dryad_circle
+// (elite)), short branch is one (thorn_tunnel). Map renders the long
+// branch as a "+1 column" arm so the topology reads at a glance.
+// Secret uses LockStatCheck WIS (not Perception) to exercise the
+// stat-check lock kind — Crypt's secret is Perception, so this is the
+// first authored zone using stat_check.
+
+func zoneForestShadowsGraph() ZoneGraph {
+	nodes := []ZoneNode{
+		{NodeID: "forest_shadows.entry", Kind: NodeKindEntry, IsEntry: true,
+			Label: "Forest Edge", PosX: 0, PosY: 1},
+		{NodeID: "forest_shadows.twisted_path", Kind: NodeKindExploration,
+			Label: "Twisted Path", PosX: 1, PosY: 1},
+		{NodeID: "forest_shadows.fork1", Kind: NodeKindFork,
+			Label: "Splintered Trail", PosX: 2, PosY: 1},
+		{NodeID: "forest_shadows.grove_descent", Kind: NodeKindExploration,
+			Label: "Grove Descent", PosX: 3, PosY: 0},
+		{NodeID: "forest_shadows.dryad_circle", Kind: NodeKindElite,
+			Label: "Dryad's Circle", PosX: 4, PosY: 0},
+		{NodeID: "forest_shadows.thorn_tunnel", Kind: NodeKindExploration,
+			Label: "Thorn Tunnel", PosX: 3, PosY: 2},
+		{NodeID: "forest_shadows.fork2", Kind: NodeKindFork,
+			Label: "Hollow King's Approach", PosX: 5, PosY: 1},
+		{NodeID: "forest_shadows.sapling_shrine", Kind: NodeKindSecret,
+			Label: "Sapling Shrine", PosX: 6, PosY: 2,
+			Content: ZoneNodeContent{LootBias: 2.0}},
+		{NodeID: "forest_shadows.boss", Kind: NodeKindBoss, IsBoss: true,
+			Label: "Throne of Antlers", PosX: 7, PosY: 1},
+	}
+	edges := []ZoneEdge{
+		{From: "forest_shadows.entry", To: "forest_shadows.twisted_path", Lock: LockNone},
+		{From: "forest_shadows.twisted_path", To: "forest_shadows.fork1", Lock: LockNone},
+		{From: "forest_shadows.fork1", To: "forest_shadows.grove_descent", Lock: LockNone, Weight: 1},
+		{From: "forest_shadows.fork1", To: "forest_shadows.thorn_tunnel",
+			Lock: LockPerception, LockData: map[string]any{"dc": 13},
+			Hint: "a deer-track winding into thicker brush", Weight: 2},
+		{From: "forest_shadows.grove_descent", To: "forest_shadows.dryad_circle", Lock: LockNone},
+		{From: "forest_shadows.dryad_circle", To: "forest_shadows.fork2", Lock: LockNone},
+		{From: "forest_shadows.thorn_tunnel", To: "forest_shadows.fork2", Lock: LockNone},
+		{From: "forest_shadows.fork2", To: "forest_shadows.boss", Lock: LockNone, Weight: 1},
+		{From: "forest_shadows.fork2", To: "forest_shadows.sapling_shrine",
+			Lock: LockStatCheck, LockData: map[string]any{"stat": "WIS", "dc": 14},
+			Hint: "a humming you can almost place — antlers, somewhere", Weight: 2},
+		{From: "forest_shadows.sapling_shrine", To: "forest_shadows.boss", Lock: LockNone},
+	}
+	return BuildGraph(ZoneForestShadows, nodes, edges)
+}
+
+func init() {
+	registerZoneGraph(zoneForestShadowsGraph())
+}