Initial stable release

This release introduces the first stable version of the high-precision π digit calculator, capable of generating tens of thousands of digits of π using the Chudnovsky algorithm with multi-threaded binary splitting.

Highlights:
🔢 Supports configurable digit precision (up to 100,000+ digits)
🧵 Multi-threaded execution with system core detection
🧮 Binary splitting for efficient term reduction
📦 Fully containerized via Docker (GMP + MPFR preinstalled)
📊 CLI progress bar and runtime timing
🛑 Signal-safe (Ctrl+C stops cleanly)
✅ Verified accuracy and consistent output across platforms

This release is ideal for benchmarking, educational use, and showcasing systems-level numerical computing in C.