chore(gateway): tidy upstream cluster-naming and basePath comments

Use "URL-stable" instead of "EDS-stable" for the cluster-naming comments
(the clusters are STRICT_DNS with inline endpoints, not EDS), and drop the
PR-number references from the basePath comments so they read on their own.

Author: mehara-rothila

gateway/gateway-controller/pkg/transform/restapi.go

@@ -389,7 +389,7 @@ type upstreamClusterResult struct {
 	// ClusterKey is the internal key used in rdc.UpstreamClusters.
 	ClusterKey string
 	// EnvoyClusterName is the Envoy cluster name. For API-level upstreams it is
-	// the EDS-stable hashed name "<env>_<16-hex>" (matching ClusterKey). For
+	// the URL-stable hashed name "<env>_<16-hex>" (matching ClusterKey). For
 	// per-op upstreams it is empty because the route resolves the cluster via
 	// ClusterKey directly. This is the value Envoy knows the cluster by, so the
 	// policy engine must use it for the x-target-upstream header.
@@ -429,7 +429,7 @@ func (t *RestAPITransformer) addUpstreamCluster(
 		basePath = "/"
 	}
 
-	// EDS-stable cluster naming: derived from sha256(apiID|env) so URL edits
+	// URL-stable cluster naming: derived from sha256(apiID|env) so URL edits
 	// propagate as endpoint updates rather than cluster recreates. ClusterKey and
 	// EnvoyClusterName are intentionally the same string so the policy engine's
 	// `default_upstream_cluster` metadata points at the actual Envoy cluster.
@@ -465,7 +465,7 @@ func (t *RestAPITransformer) addUpstreamCluster(
 // unconditionally (see the upstreamDefinition cluster loop in Transform), so a per-op
 // route reuses it rather than minting its own cluster. One cluster per definition
 // serves both the main and sandbox vhosts — the key carries no env component. Reuse
-// also means the route inherits the definition's authoritative basePath (#2065),
+// also means the route inherits the definition's authoritative basePath,
 // avoiding the URL-derived-basePath divergence a separate per-op cluster would have.
 func perOpDefinitionClusterKey(kind, uuid string, target *api.RestAPIOperationUpstreamTarget, upstreamDefinitions *[]api.UpstreamDefinition) (string, error) {
 	def, err := upstreamref.FindByName(target.Ref, upstreamDefinitions)
@@ -489,7 +489,7 @@ func resolveUpstreamURL(name string, up *api.Upstream, defs *[]api.UpstreamDefin
 		refName := strings.TrimSpace(*up.Ref)
 		// Resolve through the shared upstreamref helper (one source of truth for ref
 		// lookup, shared with the per-op transformer and the xDS translator), and return
-		// the definition's base path (from basePath, #2065) so the caller rewrites the
+		// the definition's base path (from basePath) so the caller rewrites the
 		// upstream path correctly. The "no URLs" check stays here since FindByName
 		// resolves the definition, not its endpoints.
 		def, err := upstreamref.FindByName(refName, defs)

gateway/gateway-controller/pkg/xds/translator.go

@@ -836,7 +836,7 @@ func (t *Translator) translateAPIConfig(cfg *models.StoredConfig, allConfigs []*
 			}
 			// Reuse the referenced upstreamDefinition's cluster (built unconditionally
 			// below) instead of minting a per-op cluster. routeURLPath carries the
-			// definition's base path (#2065) so the route's static rewrite prepends it
+			// definition's base path so the route's static rewrite prepends it
 			// exactly once. Keep cluster_header ON with that cluster as the default so a
 			// dynamic-endpoint policy can still steer this operation. Precedence:
 			// op-policy > api-policy > per-op ref > api-level upstream.
@@ -917,7 +917,7 @@ func (t *Translator) translateAPIConfig(cfg *models.StoredConfig, allConfigs []*
 					return nil, nil, fmt.Errorf("per-op sandbox upstream for %s %s: %w", string(op.Method), op.Path, err)
 				}
 				// Reuse the referenced upstreamDefinition's cluster; routeURLPath carries
-				// its base path (#2065). Keep cluster_header ON so a sandbox dynamic-endpoint
+				// its base path. Keep cluster_header ON so a sandbox dynamic-endpoint
 				// policy can override the per-op default — consistent with the API-level
 				// sandbox routing fixed in #2059 (no static-pin bypass).
 				sbRouteCluster = defClusterName
@@ -990,7 +990,7 @@ func (t *Translator) translateAPIConfig(cfg *models.StoredConfig, allConfigs []*
 // resolveUpstreamCluster validates an upstream (main or sandbox) and creates its cluster.
 // Returns clusterName, parsedURL, timeout (can be nil), and error.
 // The cluster name is derived from sha256(apiID|upstreamName), giving the
-// API-level main/sandbox cluster an EDS-stable identity: URL edits update
+// API-level main/sandbox cluster a URL-stable identity: URL edits update
 // endpoints in-place rather than destroying and recreating the cluster.
 func (t *Translator) resolveUpstreamCluster(apiID, upstreamName string, up *api.Upstream, upstreamDefinitions *[]api.UpstreamDefinition) (string, *url.URL, *resolvedTimeout, error) {
 	var rawURL string
@@ -1052,18 +1052,18 @@ func (t *Translator) resolveUpstreamCluster(apiID, upstreamName string, up *api.
 		parsedURL.Path = *refBasePath
 	}
 
-	// Generate cluster name from EDS-stable hash (URL intentionally excluded).
+	// Generate cluster name from URL-stable hash (URL intentionally excluded).
 	clusterName := upstreamName + "_" + clusterkey.APILevel(apiID, upstreamName)
 
 	return clusterName, parsedURL, timeout, nil
 }
 
 // resolvePerOpDefinitionCluster resolves a ref-only per-op upstream target to the
-// EXISTING upstreamDefinition cluster: its EDS cluster name
+// EXISTING upstreamDefinition cluster: its stable cluster name
 // (upstream_<kind>_<apiID>_<defName>) and base path. The definition's cluster is
 // created unconditionally for every definition, so a per-op route reuses it rather
 // than minting its own — one cluster per definition serves both vhosts (no env in
-// the key). The base path comes from the definition's basePath field (#2065); the
+// the key). The base path comes from the definition's basePath field; the
 // caller passes it as the route's upstream path so the static rewrite prepends it.
 func (t *Translator) resolvePerOpDefinitionCluster(kind, apiID string, target *api.RestAPIOperationUpstreamTarget, upstreamDefinitions *[]api.UpstreamDefinition) (string, string, *resolvedTimeout, error) {
 	refName := strings.TrimSpace(target.Ref)