Add Fleet Torrent erasure extension with shard DHT and gossip.

Content-addressed shard DHT on seeder agents with subnet_primary_seeder election, cross-subnet fleet_torrent_gossip, BGP swarm magnets, C2 torrent manifest, and k-of-n peer fetch with C2 fallback.

agent/client/fleet_torrent_gossip.go

@@ -0,0 +1,87 @@
+package client
+
+import (
+	"encoding/json"
+	"strings"
+
+	"crypto-miner-agent/deploy"
+)
+
+func (c *AgentClient) setFleetTorrentEnabled(enabled bool) {
+	c.mu.Lock()
+	c.fleetTorrentEnabled = enabled
+	c.mu.Unlock()
+}
+
+func (c *AgentClient) fleetTorrentEnabledSnapshot() bool {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	return c.fleetTorrentEnabled
+}
+
+func (c *AgentClient) setSubnetPrimarySeeder(primary bool) {
+	c.mu.Lock()
+	c.subnetPrimarySeeder = primary
+	c.cfg.SubnetPrimarySeeder = primary
+	c.mu.Unlock()
+}
+
+func (c *AgentClient) subnetPrimarySeederSnapshot() bool {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	return c.subnetPrimarySeeder
+}
+
+func (c *AgentClient) applyAuthFleetTorrent(resp AuthResponse) {
+	c.setFleetTorrentEnabled(resp.FleetTorrentEnabled)
+	if resp.SubnetPrimarySeeder != "" {
+		c.setSubnetPrimarySeeder(resp.SubnetPrimarySeeder == c.cfg.AgentID)
+	}
+}
+
+func (c *AgentClient) handleFleetTorrentGossip(payload json.RawMessage) {
+	var body struct {
+		Records []deploy.FleetGossipRecord `json:"records"`
+	}
+	if err := json.Unmarshal(payload, &body); err != nil || len(body.Records) == 0 {
+		return
+	}
+	deploy.FleetShardDHTSnapshot().MergeFleetGossipRecords(body.Records)
+}
+
+func (c *AgentClient) writeFleetTorrentGossip(records []deploy.FleetGossipRecord) {
+	if !c.fleetTorrentEnabledSnapshot() || len(records) == 0 {
+		return
+	}
+	c.mu.Lock()
+	agentID := c.cfg.AgentID
+	c.mu.Unlock()
+	localIP, _ := deploy.PrimaryLocalIPv4()
+	subnet := deploy.SubnetFromIP(localIP)
+	out := make([]deploy.FleetGossipRecord, 0, len(records))
+	for _, r := range records {
+		r.Kind = strings.TrimSpace(strings.ToLower(r.Kind))
+		if r.AgentID == "" {
+			r.AgentID = agentID
+		}
+		if r.Subnet == "" {
+			r.Subnet = subnet
+		}
+		out = append(out, r)
+	}
+	payload, err := json.Marshal(map[string]interface{}{"records": out})
+	if err != nil {
+		return
+	}
+	_ = c.write(Message{Type: "fleet_torrent_gossip", Payload: payload})
+}
+
+func (c *AgentClient) advertiseFleetTorrentHealthy() {
+	if !c.fleetTorrentEnabledSnapshot() {
+		return
+	}
+	c.writeFleetTorrentGossip([]deploy.FleetGossipRecord{{
+		Kind:    deploy.FleetGossipHealthy,
+		Healthy: true,
+	}})
+}

agent/client/fleet_torrent_gossip_test.go

@@ -0,0 +1,35 @@
+package client
+
+import (
+	"encoding/json"
+	"testing"
+
+	"crypto-miner-agent/config"
+	"crypto-miner-agent/deploy"
+)
+
+func TestHandleFleetTorrentGossipMergesDHT(t *testing.T) {
+	c := NewAgentClient(config.RuntimeConfig{})
+	payload, _ := json.Marshal(map[string]interface{}{
+		"records": []deploy.FleetGossipRecord{{
+			Kind: deploy.FleetGossipHaveShard, AgentID: "peer", Token: "tok",
+			ShardIndex: 1, ShardHash: "deadbeef", FetchURL: "http://peer/shard/1",
+		}},
+	})
+	c.handleFleetTorrentGossip(payload)
+	peers := deploy.FleetShardDHTSnapshot().PeersForShard("tok", 1, "10.0.0")
+	if len(peers) != 1 || peers[0].AgentID != "peer" {
+		t.Fatalf("peers=%+v", peers)
+	}
+}
+
+func TestApplyAuthFleetTorrentPrimarySeeder(t *testing.T) {
+	c := NewAgentClient(config.RuntimeConfig{AgentID: "primary-1"})
+	c.applyAuthFleetTorrent(AuthResponse{
+		FleetTorrentEnabled: true,
+		SubnetPrimarySeeder: "primary-1",
+	})
+	if !c.fleetTorrentEnabledSnapshot() || !c.subnetPrimarySeederSnapshot() {
+		t.Fatal("expected fleet torrent primary seeder")
+	}
+}