Add watermark to public trust center documents

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

go.mod

@@ -18,6 +18,7 @@ require (
 	github.com/jackc/pgx/v5 v5.7.5
 	github.com/jhillyerd/enmime v1.3.0
 	github.com/openai/openai-go v1.8.2
+	github.com/pdfcpu/pdfcpu v0.11.0
 	github.com/prometheus/client_golang v1.22.0
 	github.com/stretchr/testify v1.10.0
 	github.com/vektah/gqlparser/v2 v2.5.30
@@ -61,6 +62,9 @@ require (
 	github.com/gorilla/websocket v1.5.3 // indirect
 	github.com/grpc-ecosystem/grpc-gateway/v2 v2.27.1 // indirect
 	github.com/hashicorp/golang-lru/v2 v2.0.7 // indirect
+	github.com/hhrutter/lzw v1.0.0 // indirect
+	github.com/hhrutter/pkcs7 v0.2.0 // indirect
+	github.com/hhrutter/tiff v1.0.2 // indirect
 	github.com/jackc/pgpassfile v1.0.0 // indirect
 	github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761 // indirect
 	github.com/jackc/puddle/v2 v2.2.2 // indirect
@@ -96,6 +100,7 @@ require (
 	go.opentelemetry.io/otel/sdk v1.37.0 // indirect
 	go.opentelemetry.io/proto/otlp v1.7.0 // indirect
 	go.yaml.in/yaml/v2 v2.4.2 // indirect
+	golang.org/x/image v0.27.0 // indirect
 	golang.org/x/mod v0.25.0 // indirect
 	golang.org/x/net v0.41.0 // indirect
 	golang.org/x/sync v0.15.0 // indirect
@@ -106,6 +111,7 @@ require (
 	google.golang.org/genproto/googleapis/rpc v0.0.0-20250603155806-513f23925822 // indirect
 	google.golang.org/grpc v1.73.0 // indirect
 	google.golang.org/protobuf v1.36.6 // indirect
+	gopkg.in/yaml.v2 v2.4.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 	sigs.k8s.io/yaml v1.5.0 // indirect
 )