test: improve Rust toolchain detection in E2E tests

Previously, isRustAvailable() only checked for rustc binary, which could
give false positives when WASM cache hits in CI (rustc present but
toolchain incomplete).

Changes:
- Check for rustc, cargo, and wasm32-unknown-unknown target
- Add skip logic to TestE2E_ScriptValidation for Rust tests
- Comprehensive toolchain validation prevents compilation failures

This fixes 3 failing tests:
- TestE2E_ScriptingAPI_ResponseModification
- TestE2E_ScriptingAPI_BothTriggers
- TestE2E_ScriptValidation/Valid_Rust

All tests now properly detect unavailable Rust environment and skip
gracefully instead of failing with 400 errors.

Author: 777genius

internal/e2e/scripting_compilation_test.go

@@ -10,6 +10,7 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
+	"strings"
 	"testing"
 	"time"
 )
@@ -580,6 +581,11 @@ func TestE2E_ScriptValidation(t *testing.T) {
 
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
+			// Skip Rust tests if toolchain is not available
+			if tt.language == "rust" && !isRustAvailable() {
+				t.Skip("Rust toolchain not available (rustc, cargo, or wasm32 target missing)")
+			}
+
 			validateReq := map[string]any{
 				"language":   tt.language,
 				"sourceCode": tt.code,
@@ -601,8 +607,25 @@ func TestE2E_ScriptValidation(t *testing.T) {
 	}
 }
 
-// Helper function to check if Rust is available
+// Helper function to check if Rust is available with full compilation capability
+// Checks for rustc, cargo, and wasm32-unknown-unknown target
 func isRustAvailable() bool {
-	cmd := exec.Command("rustc", "--version")
-	return cmd.Run() == nil
+	// Check if rustc exists
+	if cmd := exec.Command("rustc", "--version"); cmd.Run() != nil {
+		return false
+	}
+
+	// Check if cargo exists
+	if cmd := exec.Command("cargo", "--version"); cmd.Run() != nil {
+		return false
+	}
+
+	// Check if wasm32-unknown-unknown target is installed
+	cmd := exec.Command("rustc", "--print", "target-list")
+	out, err := cmd.Output()
+	if err != nil {
+		return false
+	}
+
+	return strings.Contains(string(out), "wasm32-unknown-unknown")
 }