feat(ssa): Complete T-test end-to-end testing with 9 bug fixes - Phase 1 core 85% complete. R service: missing value auto-filter. Backend: error handling, variable matching, dynamic filename. Frontend: module activation, session isolation, error propagation. Full flow verified.

Co-authored-by: Cursor <cursoragent@cursor.com>

r-statistics-service/utils/guardrails.R

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+# utils/guardrails.R
+# 统计护栏函数库
+
+library(glue)
+
+# 大样本优化阈值
+LARGE_SAMPLE_THRESHOLD <- 5000
+
+# 护栏 Action 类型
+ACTION_BLOCK <- "Block"    # 阻止执行
+ACTION_WARN <- "Warn"      # 警告但继续
+ACTION_SWITCH <- "Switch"  # 切换到备选方法
+
+# 正态性检验（支持三种 Action）
+check_normality <- function(values, alpha = 0.05, action = ACTION_SWITCH, action_target = NULL) {
+  n <- length(values)
+  
+  # 样本量过小
+  if (n < 3) {
+    return(list(
+      passed = TRUE, 
+      action = NULL,
+      action_target = NULL,
+      reason = "样本量过小，跳过正态性检验", 
+      skipped = TRUE
+    ))
+  }
+  
+  # 大样本优化：N > 5000 时使用抽样检验
+  if (n > LARGE_SAMPLE_THRESHOLD) {
+    set.seed(42)
+    sampled_values <- sample(values, 1000)
+    test <- shapiro.test(sampled_values)
+    passed <- test$p.value >= alpha
+    
+    return(list(
+      passed = passed,
+      action = if (passed) NULL else action,
+      action_target = if (passed) NULL else action_target,
+      p_value = test$p.value,
+      reason = glue("大样本(N={n})抽样检验，{if (passed) '满足正态性' else '不满足正态性'}"),
+      sampled = TRUE,
+      sample_size = 1000
+    ))
+  }
+  
+  # 常规检验
+  test <- shapiro.test(values)
+  passed <- test$p.value >= alpha
+  
+  return(list(
+    passed = passed,
+    action = if (passed) NULL else action,
+    action_target = if (passed) NULL else action_target,
+    p_value = test$p.value,
+    reason = if (passed) "满足正态性" else "不满足正态性",
+    sampled = FALSE
+  ))
+}
+
+# 方差齐性检验 (Levene)
+check_homogeneity <- function(df, group_var, value_var, alpha = 0.05, action = ACTION_WARN) {
+  library(car)
+  
+  formula <- as.formula(paste(value_var, "~", group_var))
+  test <- leveneTest(formula, data = df)
+  p_val <- test$`Pr(>F)`[1]
+  passed <- p_val >= alpha
+  
+  return(list(
+    passed = passed,
+    action = if (passed) NULL else action,
+    p_value = p_val,
+    reason = if (passed) "方差齐性满足" else "方差不齐性"
+  ))
+}
+
+# 样本量检验
+check_sample_size <- function(n, min_required = 3, action = ACTION_BLOCK) {
+  passed <- n >= min_required
+  return(list(
+    passed = passed,
+    action = if (passed) NULL else action,
+    n = n,
+    reason = if (passed) "样本量充足" else paste0("样本量不足, 需要至少 ", min_required)
+  ))
+}
+
+# 执行护栏链（按 check_order 顺序执行）
+run_guardrail_chain <- function(guardrail_results) {
+  warnings <- c()
+  
+  for (result in guardrail_results) {
+    if (!result$passed) {
+      if (result$action == ACTION_BLOCK) {
+        return(list(
+          status = "blocked",
+          reason = result$reason
+        ))
+      } else if (result$action == ACTION_SWITCH) {
+        return(list(
+          status = "switch",
+          target_tool = result$action_target,
+          reason = result$reason
+        ))
+      } else if (result$action == ACTION_WARN) {
+        warnings <- c(warnings, result$reason)
+      }
+    }
+  }
+  
+  return(list(
+    status = "passed",
+    warnings = warnings
+  ))
+}