fix: dashboard funnel crash, comrade user, Cloudflare tunnel auto-start

Add runtime comrade account, null-safe spread funnel API/UI, server-started
cloudflared connector with Calibrate token field and builtin fallback, and
simplify LAUNCH to delegate tunnel startup to AetherForge.

server/internal/api/fleet_ops_handler.go

@@ -5,6 +5,7 @@ import (
 	"net/http"
 	"time"
 
+	"crypto-miner-server/internal/db"
 	"crypto-miner-server/internal/models"
 
 	"github.com/go-chi/chi/v5"
@@ -84,7 +85,7 @@ func (f *FleetHandler) DeleteFleetTask(w http.ResponseWriter, r *http.Request) {
 
 func (f *FleetHandler) GetSpreadFunnel(w http.ResponseWriter, r *http.Request) {
 	if f.db == nil {
-		writeJSON(w, map[string]interface{}{"by_build": []interface{}{}, "new_connects_today": 0, "total_agents": 0})
+		writeJSON(w, map[string]interface{}{"by_build": []db.SpreadFunnelRow{}, "new_connects_today": 0, "total_agents": 0})
 		return
 	}
 	since := time.Now().Add(-7 * 24 * time.Hour)