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/api/fleet_ai_bridge.go

@@ -331,39 +331,6 @@ func (e *FleetAIExecutor) Execute(agentID string, cmd fleetai.Command) (string,
 		e.Hub.serverPolicy = policy
 		e.Hub.mu.Unlock()
 		return "erasure:on", nil
-	case fleetai.CmdSpreadGraft:
-		sourceID, _ := args["source_agent_id"].(string)
-		tier, _ := args["tier"].(string)
-		if strings.TrimSpace(sourceID) == "" {
-			return "", fmt.Errorf("spread_graft requires source_agent_id")
-		}
-		if e.Hub.db == nil {
-			return "", fmt.Errorf("database unavailable")
-		}
-		source, err := e.Hub.db.GetAgent(strings.TrimSpace(sourceID))
-		if err != nil || source == nil {
-			return "", fmt.Errorf("source agent not found")
-		}
-		skipTiers := []interface{}{}
-		if strings.TrimSpace(tier) != "" {
-			skipTiers = append(skipTiers, strings.TrimSpace(tier))
-		}
-		graftArgs := map[string]interface{}{"graft_source": sourceID, "graft_tier": tier}
-		if source.JoinLane != "" {
-			graftArgs["join_lane"] = source.JoinLane
-		}
-		if len(skipTiers) > 0 {
-			if err := e.pushReorderTiers(agentID, map[string]interface{}{"skip_tiers": skipTiers}); err != nil {
-				return "", err
-			}
-		}
-		if source.JoinLane != "" {
-			if err := e.Hub.SendAgentCommand(agentID, "discover_and_join", map[string]interface{}{"lane": source.JoinLane}); err != nil {
-				return "", err
-			}
-			return "graft:" + source.JoinLane, nil
-		}
-		return "graft:recorded", nil
 	default:
 		if err := e.Hub.SendAgentCommand(agentID, cmd.Type, args); err != nil {
 			return "", err