Website/script infra: add info regarding /graphql suffix

Author: dannywillems

website/docs/developers/scripts/infrastructure/query-block-height.sh

@@ -1,6 +1,7 @@
 #!/bin/bash
 # Usage: $0 GRAPHQL_ENDPOINT
-# GRAPHQL_ENDPOINT: GraphQL endpoint URL (required)
+# GRAPHQL_ENDPOINT: GraphQL endpoint URL (required, must end with /graphql)
+# Example: https://mina-rust-plain-2.gcp.o1test.net/graphql
 
 if [ -z "$1" ]; then
     echo "Error: GRAPHQL_ENDPOINT is required"

website/docs/developers/scripts/infrastructure/query-daemon-status.sh

@@ -1,6 +1,7 @@
 #!/bin/bash
 # Usage: $0 GRAPHQL_ENDPOINT
-# GRAPHQL_ENDPOINT: GraphQL endpoint URL (required)
+# GRAPHQL_ENDPOINT: GraphQL endpoint URL (required, must end with /graphql)
+# Example: https://mina-rust-plain-2.gcp.o1test.net/graphql
 
 if [ -z "$1" ]; then
     echo "Error: GRAPHQL_ENDPOINT is required"

website/docs/developers/scripts/infrastructure/query-peers.sh

@@ -1,6 +1,7 @@
 #!/bin/bash
 # Usage: $0 GRAPHQL_ENDPOINT
-# GRAPHQL_ENDPOINT: GraphQL endpoint URL (required)
+# GRAPHQL_ENDPOINT: GraphQL endpoint URL (required, must end with /graphql)
+# Example: https://mina-rust-plain-2.gcp.o1test.net/graphql
 
 if [ -z "$1" ]; then
     echo "Error: GRAPHQL_ENDPOINT is required"

website/docs/developers/scripts/infrastructure/test-graphql-endpoint.sh

@@ -1,6 +1,7 @@
 #!/bin/bash
 # Usage: $0 GRAPHQL_ENDPOINT
-# GRAPHQL_ENDPOINT: GraphQL endpoint URL (required)
+# GRAPHQL_ENDPOINT: GraphQL endpoint URL (required, must end with /graphql)
+# Example: https://mina-rust-plain-2.gcp.o1test.net/graphql
 
 if [ -z "$1" ]; then
     echo "Error: GRAPHQL_ENDPOINT is required"

website/docs/node-operators/infrastructure/plain-nodes.mdx

@@ -109,6 +109,21 @@ If you cannot connect to plain nodes:
 
 Common API issues:
 
+<!-- prettier-ignore-start -->
+
+:::caution GraphQL Endpoint URL Format
+
+When using plain node endpoints, **always include `/graphql` at the end of the
+URL**. The endpoint will return "HTTP method not allowed" if you omit the
+`/graphql` path.
+
+**Correct**: `https://mina-rust-plain-2.gcp.o1test.net/graphql`
+**Incorrect**: `https://mina-rust-plain-2.gcp.o1test.net/`
+
+:::
+
+<!-- prettier-ignore-stop -->
+
 <CodeBlock
   language="bash"
   title="website/docs/developers/scripts/infrastructure/test-connectivity.sh"