docs: README, plan, guides and the site describe what is built now

README: rewritten around what runs (Linux software, Xorg, apk, Linux's drivers), the honest gaps, measured numbers.
plan/: 1.0.md is the finish line, where each clause of the acceptance test stands, and the register (one failing
clause: a root that survives a reboot); built plans (foundations, hybrid, alpine, xorg) and the decided-against one
(wayland) are gone, their content lives in architecture/; roadmap.md is only what is still open.
guides: building/layout/testing/adding-a-driver (Linux code may be used). history: four entries (ls -lR, TLB
shootdowns, MDIO 0x02460246, netlink MSG_TRUNC). Website: cards, stack, download page, docs index.
Code comments that pointed at deleted plan docs point at the architecture docs.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EVRhxi9zpdW2uDUN4FVcao

kernel/drivers/gpu/vga/vga_fb.c

@@ -272,7 +272,7 @@ const struct display_ops vga_display_ops = {
 // driver that leaves has to name its replacement rather than simply detaching;
 // detaching alone leaves gfx pointing at a device nobody is driving.
 //
-// This is the fallback rule from docs/plan/hybrid.md made real: the kernel
+// This is the fallback rule from docs/architecture/devices.md made real: the kernel
 // keeps a minimal driver for everything on the path to a shell, so a fancy
 // driver leaving degrades to a working screen instead of to no screen.
 int