feat(install): Add installer script Termux build support

[mcpe500]

This pull request significantly improves the installation and development experience for kolosal-cli by introducing a set of powerful new scripts. The primary goal is to lower the barrier to entry for new users across multiple platforms and streamline the build process for Termux developers.

What's New? 🚀

• Unified Installer Script (install-kolosal-termux.sh):

  • A single, intelligent script that automatically detects the user's operating system (macOS, Debian/Ubuntu, Windows, Termux).
  • For most platforms, it downloads the appropriate pre-compiled release artifact (.dmg, .deb, .exe) and handles the installation process.
  • Provides clear instructions for Termux users to build from source, as pre-compiled binaries are not used for that platform.
  • Supports both headless (default) and interactive/GUI-launch modes (--launch).

• Termux Build Script (build-kolosal-cli.sh):

  • A dedicated script to compile kolosal-cli from source directly within the Termux environment.
  • Automatically checks for and installs required dependencies (cmake, make, clang, libraries).
  • Initializes and updates all necessary Git submodules.
  • Handles the entire cmake and make process.

• Convenience Runner Script (run-kolosal.sh):

  • A simple wrapper script that allows executing the locally-built kolosal binary from the project's root directory without needing to navigate into build/bin.