feat: initial backend scaffolding

migrating away from convex

Co-authored-by: Ona <no-reply@ona.com>

apps/backend/internal/drexa/err.go

@@ -0,0 +1,23 @@
+package drexa
+
+import (
+	"fmt"
+	"strings"
+)
+
+type ServerConfigError struct {
+	Errors []error
+}
+
+func NewServerConfigError(errs ...error) *ServerConfigError {
+	return &ServerConfigError{Errors: errs}
+}
+
+func (e *ServerConfigError) Error() string {
+	sb := strings.Builder{}
+	sb.WriteString("invalid server config:\n")
+	for _, err := range e.Errors {
+		sb.WriteString(fmt.Sprintf("  - %s\n", err.Error()))
+	}
+	return sb.String()
+}