Add READMEs for the repo and every generation, root CLAUDE.md and .gitattributes

The root README has the timeline of all generations since 2009. Each generation folder explains its hardware and what is in it. .gitattributes turns off line-ending conversion so all files stay as they were.

2009-fpga/README.md

@@ -0,0 +1,9 @@
+# 2009–2011: the FPGA version
+
+The first hexapod, built on the original frame (`../original-frame/`) and driven by an FPGA.
+The FPGA code has not survived; what is left are the photos and videos in `media/`, among them
+`hexapod film 18-11-09.wmv`.
+
+`media/` holds every hexapod photo and video created on or before 2 November 2011 20:44:07; everything later
+is in `../2011-firefly-mega-ssc32/media/`. (Most dates are copy dates, so the split follows the owner's check
+of the files, not the exact moment each photo was taken. `DSCF*` photos carry a camera date of 2003.)