Integrate wave-based scaling system with WHOOSH server

- Add scaling system components to server initialization
- Register scaling API and assignment broker routes
- Start bootstrap pool manager in server lifecycle
- Add graceful shutdown for scaling controller
- Update API routing to use chi.Router instead of gorilla/mux
- Fix Docker API compatibility issues
- Configure health gates with placeholder URLs for KACHING and BACKBEAT

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

internal/orchestrator/health_gates.go

@@ -9,7 +9,6 @@ import (
 
 	"github.com/rs/zerolog/log"
 	"go.opentelemetry.io/otel/attribute"
-	"go.opentelemetry.io/otel/trace"
 
 	"github.com/chorus-services/whoosh/internal/tracing"
 )