Fix integer overflow warning in MarkPullRequestReadyForReview

- Add bounds checking when converting int to int32 for pullNumber
- Use int32 variable in githubv4.Int() conversion to avoid gosec G115 warning
- Resolves linting issue while maintaining type safety

Author: efouts

pkg/github/pullrequests.go

@@ -1643,6 +1643,12 @@ func MarkPullRequestReadyForReview(getGQLClient GetGQLClientFn, t translations.T
 				return mcp.NewToolResultError(err.Error()), nil
 			}
 
+			// Convert int to int32 with bounds checking to avoid integer overflow
+			if pullNumber < 0 || pullNumber > 2147483647 {
+				return mcp.NewToolResultError("pullNumber out of range for int32"), nil
+			}
+			pullNumber32 := int32(pullNumber)
+
 			// Get the GraphQL client
 			client, err := getGQLClient(ctx)
 			if err != nil {
@@ -1662,7 +1668,7 @@ func MarkPullRequestReadyForReview(getGQLClient GetGQLClientFn, t translations.T
 			variables := map[string]any{
 				"owner": githubv4.String(owner),
 				"repo":  githubv4.String(repo),
-				"prNum": githubv4.Int(pullNumber),
+				"prNum": githubv4.Int(pullNumber32),
 			}
 
 			if err := client.Query(ctx, &getPullRequestQuery, variables); err != nil {