feat: add extended language validators and fix tokenizer crash bugs

Expand nimcheck with validators and tokenizers for C, C++, C#, Go, Rust,
Ruby, CSS, SQL, Markdown, Dockerfile, Makefile, Kotlin, Lua, Swift,
TypeScript, and XML. Register all flavors in the validator factory and
improve auto-detection scoring for the new languages.

Fix infinite tokenizer loops that caused OOM kills: closeBracket now
advances position, finishTokenizeStep guards stalled tokenization, and
Jinja/JS tokenizers no longer double-advance on brackets.

Fix block-balance false positives in Lua (for/do) and Ruby (postfix
unless), SQL trailing-comma detection across whitespace, and Makefile
tab literals in test fixtures.

tests/fixtures/cpp/edge_cases.cpp

@@ -0,0 +1,46 @@
+#include <iostream>
+#include <string>
+#include <vector>
+#include <locale>
+#include <codecvt>
+
+/* Unicode comment: 你好, 世界, 🌍🚀 */
+
+int main() {
+    // Unicode string literals
+    std::string utf8 = "こんにちは世界";
+    std::cout << utf8 << std::endl;
+
+    // Null byte in string
+    std::string null_str = std::string("hello\x00world", 11);
+    std::cout << "Null-str size: " << null_str.size() << std::endl;
+
+    // Deeply nested templates
+    template <typename T>
+    struct Wrap { T value; };
+
+    Wrap<Wrap<Wrap<Wrap<Wrap<Wrap<Wrap<Wrap<int>>>>>>>> deep = {{{{{{{{42}}}}}}}};
+    std::cout << deep.value.value.value.value.value.value.value.value << std::endl;
+
+    // Extremely long string
+    std::string long_str(10000, 'x');
+    std::cout << "Long string length: " << long_str.length() << std::endl;
+
+    // BOM-like bytes
+    const unsigned char bom[] = {0xEF, 0xBB, 0xBF, 'H', 'i', 0};
+    std::cout << reinterpret_cast<const char*>(bom) << std::endl;
+
+    // Deep lambda nesting
+    auto f1 = [](int x) {
+        return [x](int y) {
+            return [x, y](int z) {
+                return [x, y, z](int w) {
+                    return x + y + z + w;
+                };
+            };
+        };
+    };
+    std::cout << "Nested lambdas: " << f1(1)(2)(3)(4) << std::endl;
+
+    return 0;
+}

tests/fixtures/cpp/invalid.cpp

@@ -0,0 +1,33 @@
+#include <iostream>
+#include <string>
+
+class Broken {
+public:
+    Broken(int x) : x_(x) {}
+
+    void show() {
+        std::cout << x_ << std::endl;
+
+    int missing_semicolon()
+        return x_;
+    }
+
+private:
+    int x_
+};
+
+int main() {
+    Broken b(42);
+    b.show()
+
+    char *s = "unclosed string;
+    std::cout << s << std::endl;
+
+    if (b.x_ > 0 {
+        std::cout << "positive" << std::endl;
+    }
+
+    std::vector<int> v = {1, 2, 3};
+    std::cout << v[5] << std::endl;
+
+    return 0;

tests/fixtures/cpp/valid.cpp

@@ -0,0 +1,58 @@
+#include <iostream>
+#include <vector>
+#include <string>
+#include <memory>
+#include <algorithm>
+
+class Person {
+public:
+    Person(int id, std::string name)
+        : id_(id), name_(std::move(name)) {}
+
+    int id() const { return id_; }
+    const std::string& name() const { return name_; }
+
+    virtual void greet() const {
+        std::cout << "Hello, I'm " << name_ << std::endl;
+    }
+
+    virtual ~Person() = default;
+
+private:
+    int id_;
+    std::string name_;
+};
+
+class Student : public Person {
+public:
+    Student(int id, std::string name, double gpa)
+        : Person(id, std::move(name)), gpa_(gpa) {}
+
+    void greet() const override {
+        std::cout << "Hi, I'm " << name() << " (GPA: " << gpa_ << ")" << std::endl;
+    }
+
+private:
+    double gpa_;
+};
+
+template <typename T>
+T max_value(T a, T b) {
+    return (a > b) ? a : b;
+}
+
+int main() {
+    auto p = std::make_unique<Student>(1, "Alice", 3.9);
+    p->greet();
+
+    std::vector<int> nums = {3, 1, 4, 1, 5, 9};
+    std::sort(nums.begin(), nums.end());
+
+    for (int n : nums) {
+        std::cout << n << " ";
+    }
+    std::cout << std::endl;
+
+    std::cout << "Max of 10 and 20: " << max_value(10, 20) << std::endl;
+    return 0;
+}