如何在带组的geom_barplot上手动添加pvalue？

library(ggplot2)

# 准备数据
data <- data.frame(
  group = c("A", "A", "B", "B"),
  value = c(10, 12, 8, 9)
)

p <- ggplot(data, aes(x = group, y = value))
p + geom_bar(stat = "identity")

# 添加pvalue
p + geom_bar(stat = "identity") +
  annotate("text", x = 1.5, y = 13, label = "p = 0.05")

# 添加多个pvalue
p <- ggplot(data, aes(x = group, y = value))
p + geom_bar(stat = "identity") +
  annotate("text", x = 1.5, y = 13, label = "p = 0.05") +
  annotate("text", x = 2.5, y = 10, label = "p = 0.10")