docs: four directories, and a rule for when a thing leaves the roadmap

docs/ was ten files where a plan, a description, a guide and a bug report all
sat next to each other. It is now architecture/ (what SchOS is), plan/ (what it
will be), guides/ (how to work on it) and history/ (why it is like this), with
an index that states the one rule holding it together: when something is
finished it moves from plan/ to architecture/ and is rewritten as a description
of the thing rather than a record of building it.

A ticked checkbox says the work happened. It does not say what the work
*produced*, and six months later the checkbox is all that is left. The network
stack proved the point: finished, verified end to end, and for a month the only
description of it anywhere was a checkbox four levels of indentation deep.

So roadmap.md went from 534 lines to 181 -- nothing deleted, the done work
graduated. Seven subsystems that were finished and undescribed now have
descriptions: boot, kernel, syscalls, filesystem, networking, graphics, usb,
init. Every one ends with "What it does not do", which is the section that pays;
a document listing only strengths is marketing, and the reader who needs it most
is the one about to trip over a limitation nobody wrote down.

schfs.md still opened with "phases 1 through 3 1/2 are done, phase 4 is next"
long after all five had landed. It is a description now, with the phase record
and the hard-won bugs moved to history/.

Three corrections found on the way, all load-bearing:

  * projects/schcom/README.md claimed SCM_RIGHTS was done. There is no
    sendmsg/recvmsg in the kernel at all, and an entire GUI plan rested on it.
  * The root README said "No TCP/IP" months after the stack landed.
  * history/kernel.md sec.7 was marked "in progress" on a problem that process
    groups solved.

Also adds plan/1.0.md, which draws a finish line so the open list stops being
infinite, and marks schwm/ and schde/ superseded: in Wayland the compositor is
the window manager, so that split dissolves rather than being abandoned.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VQ7Qx8E1q1M1bbCq8QLHS2

projects/schde/README.md

@@ -1,5 +1,12 @@
 # SchDE — the SchOS Desktop Environment
 
+> **Superseded as a directory, not as an idea.** A panel, a launcher and a
+> settings app are ordinary Wayland clients using `wlr-layer-shell`. This
+> directory is to be deleted; they need no home of their own until one of them
+> is written.
+>
+> See [`docs/plan/wayland.md`](../../docs/plan/wayland.md).
+
 The parts you actually look at: a panel, a launcher, settings, a file
 manager, a terminal.
 
@@ -16,7 +23,7 @@ designing a panel before there is a compositor to put it on.
 ## What it will need that does not exist yet
 
 - **Text rendering.** Everything here is text, and the console's fixed 8×16
-  CP437 grid is not usable for it. See phase 4 of `docs/roadmap.md` — a real
+  CP437 grid is not usable for it. See `docs/plan/wayland.md` — a real
   glyph cache and rasteriser, and layout as a library in `lib/` so the
   terminal and the file manager are not each solving it.
 - **A widget toolkit**, however small. Even a panel needs buttons, labels and