fix(gists): Use proper GitHub API error handling for observability

The gists.go file was using NewToolResultErrorFromErr for GitHub API
errors, which breaks the error middleware tracking that the remote
server uses for observability and incident detection.

Changed API errors (client.Gists.List, Get, Create, Edit) to use
ghErrors.NewGitHubAPIErrorResponse which properly:
- Records errors in the context for middleware access
- Preserves the response object for rate limit and status tracking
- Maintains consistency with other tools that use this pattern

This ensures production observability is maintained for Gist operations.

Author: SamMorrowDrums

pkg/github/gists.go

@@ -7,6 +7,7 @@ import (
 	"io"
 	"net/http"
 
+	ghErrors "github.com/github/github-mcp-server/pkg/errors"
 	"github.com/github/github-mcp-server/pkg/registry"
 	"github.com/github/github-mcp-server/pkg/translations"
 	"github.com/github/github-mcp-server/pkg/utils"
@@ -80,7 +81,7 @@ func ListGists(t translations.TranslationHelperFunc) registry.ServerTool {
 
 				gists, resp, err := client.Gists.List(ctx, username, opts)
 				if err != nil {
-					return utils.NewToolResultErrorFromErr("failed to list gists", err), nil, nil
+					return ghErrors.NewGitHubAPIErrorResponse(ctx, "failed to list gists", resp, err), nil, nil
 				}
 				defer func() { _ = resp.Body.Close() }()
 
@@ -139,7 +140,7 @@ func GetGist(t translations.TranslationHelperFunc) registry.ServerTool {
 
 				gist, resp, err := client.Gists.Get(ctx, gistID)
 				if err != nil {
-					return utils.NewToolResultErrorFromErr("failed to get gist", err), nil, nil
+					return ghErrors.NewGitHubAPIErrorResponse(ctx, "failed to get gist", resp, err), nil, nil
 				}
 				defer func() { _ = resp.Body.Close() }()
 
@@ -238,7 +239,7 @@ func CreateGist(t translations.TranslationHelperFunc) registry.ServerTool {
 
 				createdGist, resp, err := client.Gists.Create(ctx, gist)
 				if err != nil {
-					return utils.NewToolResultErrorFromErr("failed to create gist", err), nil, nil
+					return ghErrors.NewGitHubAPIErrorResponse(ctx, "failed to create gist", resp, err), nil, nil
 				}
 				defer func() { _ = resp.Body.Close() }()
 
@@ -340,7 +341,7 @@ func UpdateGist(t translations.TranslationHelperFunc) registry.ServerTool {
 
 				updatedGist, resp, err := client.Gists.Edit(ctx, gistID, gist)
 				if err != nil {
-					return utils.NewToolResultErrorFromErr("failed to update gist", err), nil, nil
+					return ghErrors.NewGitHubAPIErrorResponse(ctx, "failed to update gist", resp, err), nil, nil
 				}
 				defer func() { _ = resp.Body.Close() }()