fix: update E2E test API paths and payloads to match backend

- user-apikey-lifecycle: /api/v1/keys -> /api/v1/api-keys (24 occurrences)
- admin-users: balance payload uses balance+operation+notes
- admin-groups: rate-multiplier already uses correct format

tests/scripts/run-tests.sh

@@ -0,0 +1,95 @@
+#!/bin/bash
+
+# Sub2API Test Runner Script
+# 
+# Usage:
+#   ./run-tests.sh           # Run all tests
+#   ./run-tests.sh unit     # Run only unit tests
+#   ./run-tests.sh e2e      # Run only E2E tests
+#   ./run-tests.sh ci       # Run tests in CI mode
+
+set -e
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+PROJECT_ROOT="$(dirname "$SCRIPT_DIR")"
+
+# Colors
+RED='\033[0;31m'
+GREEN='\033[0;32m'
+YELLOW='\033[1;33m'
+NC='\033[0m' # No Color
+
+log_info() {
+    echo -e "${GREEN}[INFO]${NC} $1"
+}
+
+log_warn() {
+    echo -e "${YELLOW}[WARN]${NC} $1"
+}
+
+log_error() {
+    echo -e "${RED}[ERROR]${NC} $1"
+}
+
+run_unit_tests() {
+    log_info "Running backend unit tests..."
+    cd "$PROJECT_ROOT/backend"
+    go test -short ./...
+    log_info "Unit tests completed!"
+}
+
+run_integration_tests() {
+    log_info "Running frontend integration tests..."
+    cd "$PROJECT_ROOT/frontend"
+    pnpm test -- --run
+    log_info "Integration tests completed!"
+}
+
+run_e2e_tests() {
+    log_info "Running E2E tests..."
+    cd "$SCRIPT_DIR"
+    npx playwright test
+    log_info "E2E tests completed!"
+}
+
+run_all_tests() {
+    log_info "Running all tests..."
+    
+    run_unit_tests
+    run_integration_tests
+    run_e2e_tests
+    
+    log_info "All tests completed!"
+}
+
+run_ci_tests() {
+    log_info "Running CI tests (without E2E)..."
+    
+    run_unit_tests
+    run_integration_tests
+    
+    log_info "CI tests completed!"
+}
+
+# Main
+case "${1:-all}" in
+    unit)
+        run_unit_tests
+        ;;
+    integration)
+        run_integration_tests
+        ;;
+    e2e)
+        run_e2e_tests
+        ;;
+    ci)
+        run_ci_tests
+        ;;
+    all)
+        run_all_tests
+        ;;
+    *)
+        echo "Usage: $0 {unit|integration|e2e|ci|all}"
+        exit 1
+        ;;
+esac