Fix Dockerfile Go version

Upgrade builder image from golang:1.24-alpine to golang:1.27-alpine
to match go.mod requirement (go 1.27.2). Go 1.24 cannot process
go.mod with go >= 1.27.2 even with GOTOOLCHAIN=local.

Dockerfile

@@ -1,5 +1,5 @@
 # Build stage
-FROM golang:1.24-alpine AS builder
+FROM golang:1.27-alpine AS builder
 
 WORKDIR /app