doc: generate README.md from README.org (Emacs batch ox-md)

Add build.el + pre-commit hook so README.org stays the source and
README.md is regenerated for GitHub/MELPA.  Refresh README (screenshots,
Crapette, use-package, new customs).  Makefile: readme/hooks/info-emacs
targets; ship README.md.

doc/card-games.texi

@@ -8,8 +8,7 @@
 @syncodeindex fn cp
 @c %**end of header
 
-@set VERSION 1.0.90
-@set YEAR 2026
+@include version.texi
 
 @copying
 This manual is for Card Games for Emacs (version @value{VERSION}), an
@@ -81,6 +80,10 @@ Card Games for Emacs is a collection of more than thirty card games ---
 solitaires, two-player games, and four-handed partnership games ---
 played entirely inside GNU Emacs.
 
+@ifnotinfo
+@center @image{images/klondike, , , Klondike solitaire in Emacs, png}
+@end ifnotinfo
+
 Every game draws itself two ways.  In a terminal it uses plain UNICODE
 text, so it works anywhere Emacs runs, including over @command{ssh} and
 on a phone.  On a graphical display it draws proper SVG cards, with a
@@ -599,6 +602,10 @@ the highest card (or the highest trump) wins it.  You sit South; the
 other three seats are computer players, and for the partnership games
 North is your partner.
 
+@ifnotinfo
+@center @image{images/hearts, , , A hand of Hearts, png}
+@end ifnotinfo
+
 @cindex trick games, controls
 Most of them share these controls:
 

doc/version.texi

@@ -0,0 +1,3 @@
+@set VERSION 1.0.90
+@set UPDATED 1 July 2026
+@set YEAR 2026