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

docs/architecture/devices.md

@@ -191,7 +191,7 @@ bitmap, and loses them when it releases or exits. Granting it is not optional
 a driver's `outl` is an instruction compiled into it, not a call anything can
 intercept — and granting it *coarsely* is not acceptable, because `IOPL=3` is
 one flag that hands over the interrupt controller and the disk along with the
-NIC. See [../../include/ioperm.h](../../include/ioperm.h).
+NIC. See [../../include/arch/ioperm.h](../../include/arch/ioperm.h).
 
 ### Handing a device over