not-working skill tree graph

mastery_tree_visualiser.r

```r
library(jsonlite)
library(igraph)
library(ggraph)
library(dplyr)
library(ggplot2)

file_path <- "./abbrev_nodes.json"
mastery_tree_data <- fromJSON(file_path)

graph <- make_empty_graph(directed = TRUE)

# sdd nodes
for (node_id in names(mastery_tree_data)) {
  node_info <- mastery_tree_data[[node_id]]
  label_text <- paste(
    node_info$name, "\nLvl", node_info$current_level, "/",
    node_info$max_level
  )
  graph <- add_vertices(graph, 1, name = node_id, label = label_text)
}

# add edges
for (node_id in names(mastery_tree_data)) {
  node_info <- mastery_tree_data[[node_id]]
  if (!is.null(node_info$children)) {
    for (child_id in node_info$children) {
      if (child_id %in% names(mastery_tree_data)) {
        graph <- add_edges(graph, c(node_id, child_id))
      }
    }
  }
}

manual_layout <- data.frame(
  name = names(mastery_tree_data),
  x = sapply(mastery_tree_data, function(x) x$col), y = sapply(
    mastery_tree_data,
    function(x) x$row
  ), stringsAsFactors = FALSE
)

manual_layout$name <- as.character(manual_layout$name)

plot <- ggraph(graph, layout = manual_layout) + geom_edge_link() +
  geom_node_point(size = 5, color = "steelblue") +
  geom_node_text(aes(label = label), repel = TRUE, size = 3, color = "black") +
  theme_void() +
  ggtitle("mastery Tree Visualization")

print(plot)
```

I've tried doing this, but it didn't change a thing:
```r
graph_width <- max(mastery_tree$x) - min(mastery_tree$x)
midpoint_x <- min(mastery_tree$x) + (graph_width/2)

desired_midpoint_x <- 0

shift_x <- desired_midpoint_x - midpoint_x

mastery_tree$x <- mastery_tree$x + shift_x

x_range <- max(mastery_tree$x) - min(mastery_tree$x)
x_lim <- c(min(mastery_tree$x) - 0.1 * x_range, max(mastery_tree$x) + 0.1 * x_range)

plot <- ggraph(graph, layout = 'manual', node.positions = mastery_tree) +
  geom_edge_link() +
  geom_node_point(size = 3) +
  geom_node_text(aes(label = label), repel = TRUE, size = 3) +
  expand_limits(x = x_lim) +
  theme(plot.margin = unit(c(1, 1, 1, 1), "cm"))
```

trying to center:

graph_width <- max(mastery_tree$x) - min(mastery_tree$x)
midpoint_x <- min(mastery_tree$x) + (graph_width/2)

desired_midpoint_x <- 0

shift_x <- desired_midpoint_x - midpoint_x

mastery_tree$x <- mastery_tree$x + shift_x

x_range <- max(mastery_tree$x) - min(mastery_tree$x)
x_lim <- c(min(mastery_tree$x) - 0.1 * x_range, max(mastery_tree$x) + 0.1 * x_range)

plot <- ggraph(graph, layout = 'manual', node.positions = mastery_tree)
  + geom_edge_link()
  + geom_node_point(size = 3)
  + geom_node_text(aes(label = label), repel = TRUE, size = 3)
  + expand_limits(x = x_lim)
  + theme(plot.margin = unit(c(1, 1, 1, 1), "cm"))