fix(v4.0.0): step 6e review round 1 -- a take that does not take does nothing; output and answers wait at a middle node; no queue on the kernel's port; a printing wait is not interrupted

- The result of every take is looked at: a wire cut between the look and
  the take leaves nothing acted on (the text before run again, a refusal
  counted, a wait ended by an old answer, a way forgotten).
- A node with no room to pass on what another printed, or its word of how
  text ended, leaves it on the wire it came by and moves it when there is
  room; what is behind it for the same port waits too.  Sleep for room (9)
  is woken by room on any of the node's wires (engine; MESH.md 7d.3).
- The lone node's host keeps no queue for the kernel's port: a message to
  it is error 18.  The step limit is counted while the node waits for room.
- A text waiting for room to print is not interrupted by console text;
  AWAIT is, as before.  (BREAK?) is gone.
- A GONE is believed only by the centre's port; unawaited answers let go
  are counted; nothing past a message's last character goes on a wire;
  AWAIT sets (AWAIT-FROM) only once the stack has been tried.
- test_host_depth.c: ten paths, each run works or ends in one named stack
  error; it fails with (ROOM) or (ROOM-SERVE) taken out.

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

v4/src/wire.c

@@ -13,6 +13,7 @@ void v4_wire_reset(v4_wire_queue *q)
     q->used = 0;
     q->mark = 0;
     q->arrived = 0;
+    q->freed = 0;
 }
 
 unsigned v4_wire_cells(v4_cell length)
@@ -89,6 +90,7 @@ static void remove_marked(v4_wire_queue *q)
         for (i = q->mark; i + n < q->used; i++) q->cell[slot(q, i)] = q->cell[slot(q, i + n)];
     }
     q->used -= n;
+    q->freed = 1;
 }
 
 int v4_wire_take(v4_wire_queue *q, v4_cell *header7, v4_cell *text, unsigned text_cap)