Full-SVG 500 made mouse-operable for newcomers: kitty Discard button and
five-card cap, on-table phase banner, ? Help/Rules overlay with the bid
legend, legal-play dimming, card-size slider, and a layout pass that
moves the Help and size controls into the log panel so nothing overlaps.
Bump all files to 1.0.90, add NEWS, a README testing quick-start, and
make the shared engine files checkdoc-clean.
cg-renderer gains a regions slot; the text/svg treatments get real
draw/hit methods; cg-regions-hit + cg-render-apply complete the loop.
Prototype on solitaire: cg-sol--svg returns (image . regions), redisplay
goes through cg-render-game, and [mouse-1] selects-and-acts by reusing the
keyboard pick-up/drop. Adds cgt-keystone-regions; suite 110/110.
