feat: Implement Session Token System with /api/v1 base path

- Add migration 000004 for sessions table and performance indexes
- Create session.sql queries for CRUD operations
- Generate session repository code with sqlc
- Create token auth middleware for Echo framework
- Create token handler with create/delete/cleanup endpoints
- Add /api/v1 router with token authentication infrastructure
- Update dbHelper.go to use Up() instead of Migrate(2)
- Update server.go to initialize token handler
- Existing endpoints remain functional (to be deprecated)

New endpoints:
- POST /api/v1/token - Create new session token
- DELETE /api/v1/token - Invalidate token
- POST /api/v1/token/cleanup - Remove expired sessions

Generated by Mistral Vibe.
Co-Authored-By: Mistral Vibe <vibe@mistral.ai>

internal/server/server.go

@@ -14,7 +14,8 @@ import (
 )
 
 type Server struct {
-	port int
+	port         int
+	tokenHandler *TokenHandler
 }
 
 var (
@@ -39,8 +40,13 @@ func NewServer() *http.Server {
 	logger := logging.GetLogger()
 
 	port, _ := strconv.Atoi(os.Getenv("PORT"))
+	
+	// Initialize token handler
+	tokenHandler := NewTokenHandler()
+	
 	NewServer := &Server{
-		port: port,
+		port:         port,
+		tokenHandler: tokenHandler,
 	}
 
 	logger.Info("Starting server",