Add casting section to style guide

style.md

@@ -72,6 +72,26 @@ signal(SIGTERM, handler);
   - Use for performance measurements, statistics, and monitoring data
   - Never use for counts, sizes, or business logic
 
+### Type Casting
+- **Never use C-style casts** - they're unsafe and can hide bugs by performing dangerous conversions
+- **Use C++ cast operators** for explicit type conversions with clear intent and safety checks
+- **Avoid `reinterpret_cast`** - almost always indicates poor design; redesign APIs instead
+- **Prefer no casts** - design APIs and use types that avoid casting entirely when possible
+
+```cpp
+// Dangerous - C-style casts (NEVER DO THIS)
+// int* ptr = (int*)malloc(sizeof(int));     // Unsafe
+// int64_t id = (int64_t)some_pointer;       // Dangerous pointer conversion
+// BaseClass* base = (BaseClass*)derived;    // Loses type safety
+
+// Acceptable C++ cast operators (use sparingly)
+auto ptr = static_cast<int*>(malloc(sizeof(int)));    // Explicit conversion
+auto base = static_cast<BaseClass*>(derived_ptr);     // Safe upcast
+auto derived = dynamic_cast<DerivedClass*>(base_ptr); // Runtime type checking
+auto mutable_ptr = const_cast<int*>(const_ptr);       // Remove const (rare)
+auto addr = reinterpret_cast<uintptr_t>(ptr);         // Low-level operations (very rare, delicate)
+```
+
 ### Performance Focus
 - **Performance-first design** - optimize for the hot path
 - **Simple is fast** - find exactly what's necessary, strip away everything else
@@ -99,9 +119,9 @@ signal(SIGTERM, handler);
 ### Variables and Functions
 - **snake_case** for all variables, functions, and member functions
 ```cpp
-size_t used_bytes() const;
+int64_t used_bytes() const;
-void add_block(size_t size);
+void add_block(int64_t size);
-uint32_t initial_block_size_;
+int32_t initial_block_size_;
 ```
 
 ### Structs
@@ -113,12 +133,12 @@ uint32_t initial_block_size_;
 ```cpp
 struct ArenaAllocator {
   // Public interface first
-  explicit ArenaAllocator(size_t initial_size = 1024);
+  explicit ArenaAllocator(int64_t initial_size = 1024);
-  void* allocate_raw(size_t size);
+  void* allocate_raw(int64_t size);
 
 private:
   // Private members after
-  uint32_t initial_block_size_;
+  int32_t initial_block_size_;
   Block* current_block_;
 };
 ```
@@ -150,7 +170,7 @@ static const WeaselJsonCallbacks json_callbacks;
 - **Trailing underscore** for private member variables
 ```cpp
 private:
-  uint32_t initial_block_size_;
+  int32_t initial_block_size_;
   Block *current_block_;
 ```
 
@@ -206,7 +226,7 @@ std::unique_ptr<Parser> parser;
 - **Delete copy operations** when inappropriate
 ```cpp
 struct ArenaAllocator {
-  explicit ArenaAllocator(size_t initial_size = 1024);
+  explicit ArenaAllocator(int64_t initial_size = 1024);
 
   // Copy construction is not allowed
   ArenaAllocator(const ArenaAllocator &) = delete;
@@ -217,7 +237,7 @@ struct ArenaAllocator {
   ArenaAllocator &operator=(ArenaAllocator &&other) noexcept;
 
 private:
-  uint32_t initial_block_size_;
+  int32_t initial_block_size_;
   Block *current_block_;
 };
 ```
@@ -431,7 +451,7 @@ When in doubt, consult the `man` page for the specific system call to see if it
  * @note Prints error to stderr and calls std::abort() if allocation fails
  */
 template <typename T>
-T *realloc(T *ptr, uint32_t old_size, uint32_t new_size);
+T *realloc(T *ptr, int32_t old_size, int32_t new_size);
 ```
 
 ### Code Comments
@@ -440,7 +460,7 @@ T *realloc(T *ptr, uint32_t old_size, uint32_t new_size);
 - **Thread safety** and ownership semantics
 ```cpp
 // Uses O(1) accumulated counters for fast retrieval
-size_t total_allocated() const;
+int64_t total_allocated() const;
 
 // Only Server can create connections - no public constructor
 Connection(struct sockaddr_storage addr, int fd, int64_t id,