* refactor(installer): split implementation into sourced modules * test(installer): harden module path coverage * fix(installer): qualify interactive privacy and engine claims The guided installer overstated local-only privacy and ranked whisper.cpp without evidence. Match PRODUCT.md: on-device local engines, optional Remote API, and the ~33 language catalog plus Auto-detect. --------- Co-authored-by: Jatin K Malik <jatinkrmalik@gmail.com>