feat: add integration tests and lint script for examples

- Add 30 integration tests that verify all examples and projects
  parse and type-check correctly
- Add scripts/lint-examples.sh for quick pre-commit validation
- Tests will catch regressions like missing `run ... with {}` syntax
  or broken escape sequences

Run with: cargo test example_tests
Or quick check: ./scripts/lint-examples.sh

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

scripts/lint-examples.sh

@@ -0,0 +1,71 @@
+#!/usr/bin/env bash
+# Lint all Lux example and project files
+# Run this before committing to catch parse/type errors early
+
+set -e
+
+RED='\033[0;31m'
+GREEN='\033[0;32m'
+NC='\033[0m' # No Color
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+ROOT_DIR="$(dirname "$SCRIPT_DIR")"
+LUX="${ROOT_DIR}/target/release/lux"
+
+# Build if needed
+if [ ! -f "$LUX" ]; then
+    echo "Building lux..."
+    cd "$ROOT_DIR" && cargo build --release
+fi
+
+FAILED=0
+PASSED=0
+
+check_file() {
+    local file="$1"
+    local output
+    # Run the file and capture output, timeout after 10s
+    if output=$(timeout 10 "$LUX" "$file" 2>&1); then
+        echo -e "${GREEN}OK${NC}: $file"
+        ((PASSED++)) || true
+    else
+        # Check if it's just a runtime error vs parse/type error
+        if echo "$output" | grep -q "Parse error\|Type error\|Type Error\|Type Mismatch"; then
+            echo -e "${RED}FAIL${NC}: $file"
+            echo "$output" | head -20
+            echo ""
+            ((FAILED++)) || true
+        else
+            # Runtime errors are OK for linting (file parses and type checks)
+            echo -e "${GREEN}OK${NC}: $file (runtime error expected)"
+            ((PASSED++)) || true
+        fi
+    fi
+}
+
+echo "=== Linting Lux Examples ==="
+echo ""
+
+for file in "$ROOT_DIR"/examples/*.lux; do
+    check_file "$file"
+done
+
+echo ""
+echo "=== Linting Lux Projects ==="
+echo ""
+
+for file in "$ROOT_DIR"/projects/*/main.lux; do
+    check_file "$file"
+done
+
+echo ""
+echo "=== Summary ==="
+echo "Passed: $PASSED"
+echo "Failed: $FAILED"
+
+if [ $FAILED -gt 0 ]; then
+    exit 1
+fi
+
+echo ""
+echo "All files pass parse and type checking!"