* docs: improve project description with narrative intro
- Replace the one-liner README intro with a more compelling narrative
that highlights key differentiators: offline, open source, multi-engine,
GPU-accelerated, and privacy-first
- Update version.py __description__ to a more descriptive one-liner
* docs: replace all em-dashes with hyphens/commas/colons
Remove all em-dash (—) characters from README.md, replacing them
with contextually appropriate alternatives (hyphens, commas, colons).
