fix: Enable CGO in Docker build for pg_query_go dependency

The pg_query_go library requires CGO to be enabled as it wraps the libpg_query C library.
Added gcc and musl-dev dependencies to the Docker build for proper compilation.

test/postgres/Dockerfile.seaweedfs

@@ -1,7 +1,7 @@
 FROM golang:1.24-alpine AS builder
 
-# Install git and other build dependencies
-RUN apk add --no-cache git make
+# Install build dependencies including gcc for CGO (required by pg_query_go)
+RUN apk add --no-cache git make gcc musl-dev
 
 # Set working directory
 WORKDIR /app
@@ -13,8 +13,8 @@ RUN go mod download
 # Copy source code
 COPY . .
 
-# Build the weed binary with all our new features
-RUN CGO_ENABLED=0 GOOS=linux go build -ldflags "-s -w" -o weed ./weed/
+# Build the weed binary with CGO enabled (required for pg_query_go)
+RUN CGO_ENABLED=1 GOOS=linux go build -ldflags "-s -w" -o weed ./weed/
 
 # Final stage - minimal runtime image
 FROM alpine:latest