revert(v4.0.0): step 6d, the wait, is backed out -- two reviews found it unsound

Ruled 2026-10-08.  The engine, the nucleus and their tests are as they
were at dfabfa46, before step 6d; the code of the wait and its tests are
in history at 075385ab..2cf37aab.  The limit of MESH.md 7b.7 stands: a
node that is stuck can hold up its neighbours until Hera kills it.

MESH.md 7c is kept as the record of the design as approved, and 7c.6 says
what was built, what the two reviews found, the cause the findings share
-- a node's message machinery runs on the stacks its text is using, and a
fault abandons whatever was in progress -- and what a second attempt
must settle before anything is built.

Kept from it, in hosted-check: a line that leaves 29 values on the stack,
and WORDS with 26 values on it.  Both hung the products at some commit of
the wait.

make -C v4 test and sanitize at both widths, hosted-check, lint; three
bare-metal boots typing both.  POST 538 of 538, word_count=317,
dict_hash=0xc0769523a47b7dc3 on all six: the hash of step 6c's code.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

v4/README.md

@@ -141,17 +141,8 @@ sixteenth to pass it on, sends a NACK to whoever waits on it; `(REFUSED)`
 counts them. `AWAIT` ends in an error if the answer is not going to come:
 "Message refused", "Node gone", or "Interrupted" when a line is typed at
 the console. `n KILL` on Hera removes node n and tells every other node it
-is gone; a node believes that only from its centre.
-
-**The wait** (`MESH.md` 7c, step 6d). A node does not write the first word
-of a message: it offers it, and sleeps until it is taken or a word comes
-for it. What a node has to pass on, the answers it has to give and the
-refusals it owes all wait with it, offered, and go when they can. So a
-node that is stuck holds up no other, within the limits `MESH.md` 7c.4
-states: text that must itself send to the stuck node waits, and a node
-begins no more text from a sender it cannot yet answer. A review found
-this unsound as first built; what it found is mended and listed under
-step 6d in `MESH.md` section 10, and has not been reviewed again.
+is gone; a node believes that only from its centre. A stuck node can hold
+up its neighbours until it is killed: `MESH.md` 7b.7 says how.
 
 **Blocks** (`MESH.md` step 6). The block words are the kernel's, as they
 are for a v3 VM: `BLOCK`, `BUFFER`, `UPDATE`, `SAVE-BUFFERS` and