refactor: remove duplicate Server methods and clean up main.go

- Removed all duplicate Server methods from main.go (630 lines)
- Fixed import conflicts and unused imports
- main.go reduced from 3,298 to 340 lines (89% reduction)
- Clean modular structure with server package handling all server functionality
- Achieved clean build with no compilation errors

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

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

server/server.go

@@ -7,46 +7,47 @@ import (
 	"os"
 	"path/filepath"
 	"sync"
+	"time"
 
-	"github.com/dgraph-io/badger/v3"
+	"github.com/dgraph-io/badger/v4"
 	"github.com/robfig/cron/v3"
 	"github.com/sirupsen/logrus"
 
-	"github.com/kalzu/kvs/auth"
-	"github.com/kalzu/kvs/cluster"
-	"github.com/kalzu/kvs/storage"
-	"github.com/kalzu/kvs/types"
+	"kvs/auth"
+	"kvs/cluster"
+	"kvs/storage"
+	"kvs/types"
 )
 
 // Server represents the KVS node
 type Server struct {
-	config        *types.Config
-	db            *badger.DB
-	mode          string // "normal", "read-only", "syncing"
-	modeMu        sync.RWMutex
-	logger        *logrus.Logger
-	httpServer    *http.Server
-	ctx           context.Context
-	cancel        context.CancelFunc
-	wg            sync.WaitGroup
-	
+	config     *types.Config
+	db         *badger.DB
+	mode       string // "normal", "read-only", "syncing"
+	modeMu     sync.RWMutex
+	logger     *logrus.Logger
+	httpServer *http.Server
+	ctx        context.Context
+	cancel     context.CancelFunc
+	wg         sync.WaitGroup
+
 	// Cluster services
 	gossipService    *cluster.GossipService
 	syncService      *cluster.SyncService
 	merkleService    *cluster.MerkleService
 	bootstrapService *cluster.BootstrapService
-	
+
 	// Storage services
 	storageService  *storage.StorageService
 	revisionService *storage.RevisionService
-	
+
 	// Phase 2: Backup system
-	cronScheduler *cron.Cron           // Cron scheduler for backups
-	backupStatus  types.BackupStatus   // Current backup status
-	backupMu      sync.RWMutex         // Protects backup status
-	
+	cronScheduler *cron.Cron         // Cron scheduler for backups
+	backupStatus  types.BackupStatus // Current backup status
+	backupMu      sync.RWMutex       // Protects backup status
+
 	// Authentication service
-	authService   *auth.AuthService
+	authService *auth.AuthService
 }
 
 // NewServer initializes and returns a new Server instance
@@ -109,7 +110,7 @@ func NewServer(config *types.Config) (*Server, error) {
 		return nil, fmt.Errorf("failed to initialize storage service: %v", err)
 	}
 	server.storageService = storageService
-	
+
 	// Initialize revision service
 	server.revisionService = storage.NewRevisionService(storageService)
 
@@ -168,9 +169,9 @@ func (s *Server) getJoinedTimestamp() int64 {
 func (s *Server) getBackupStatus() types.BackupStatus {
 	s.backupMu.RLock()
 	defer s.backupMu.RUnlock()
-	
+
 	status := s.backupStatus
-	
+
 	// Calculate next backup time if scheduler is running
 	if s.cronScheduler != nil && len(s.cronScheduler.Entries()) > 0 {
 		nextRun := s.cronScheduler.Entries()[0].Next
@@ -178,6 +179,6 @@ func (s *Server) getBackupStatus() types.BackupStatus {
 			status.NextBackupTime = nextRun.Unix()
 		}
 	}
-	
+
 	return status
-}
+}