feat(v4.0.0): the wait replaces looking and the console release; step 6d written up

The engine's console release (v4_fabric_interrupt_error), a device's
pending, and the count of words since a look are removed: nothing uses
them.  MESH.md 4.1, 7b and 7c say what was built, where it differs from
what was approved and why, and what is still a limit; step 6d is marked
built, with the defects found on the way.

make -C v4 test and sanitize at both widths, hosted-check, lint; three
bare-metal boots.  POST 538 of 538, word_count=317,
dict_hash=0x6a39c0bb9d183418 on all six.

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

v4/README.md

@@ -141,8 +141,14 @@ 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. A stuck node can hold
-up its neighbours until it is killed: `MESH.md` 7b.7 says how.
+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: only text that must itself send to
+the stuck node waits, and on Hera a typed line ends that.
 
 **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