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/plan/schapi.md

@@ -1,6 +1,9 @@
 # SchAPI, and SchOS as a system
 
-Status: **direction agreed, not yet implemented.** Nothing in this document
+Status: **direction agreed, not yet implemented**, and frozen until 1.0 ships
+([1.0.md](1.0.md)). Read it as a direction and not as a schedule: written when the plan was a
+compositor of SchOS's own, it has not been revisited since the desktop became Xorg and the
+packages became Alpine's, and §7 (what happens now) in particular predates both. Nothing in this document
 changes what is being built this week; it changes what everything is being
 built *towards*. See §7 for what actually happens now.