Serialize gqlgen codegen to fix build cache race

Parallel gqlgen instances race on the Go build cache, causing
Rewriter.getSource() to panic with "slice bounds out of range"
when go/packages returns empty source. Chain gqlgen targets with
order-only prerequisites in the Makefile and switch the CI build
job to sequential generation.

Signed-off-by: Sacha Al Himdani <sacha@getprobo.com>

.github/workflows/make.yaml

@@ -216,12 +216,10 @@ jobs:
           echo dev-server > packages/emails/dist/placeholder
       - name: "Generate Go code"
         run: |
-          pids=()
-          go generate ./pkg/server/api/connect/v1 & pids+=($!)
-          go generate ./pkg/server/api/console/v1 & pids+=($!)
-          go generate ./pkg/server/api/trust/v1 & pids+=($!)
-          go generate ./pkg/server/api/mcp/v1 & pids+=($!)
-          for pid in "${pids[@]}"; do wait "$pid"; done
+          go generate ./pkg/server/api/connect/v1
+          go generate ./pkg/server/api/console/v1
+          go generate ./pkg/server/api/trust/v1
+          go generate ./pkg/server/api/mcp/v1
       - name: "Build binaries"
         env:
           CGO_ENABLED: "0"