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/tests/test_host_unit.c

@@ -490,7 +490,8 @@ int main(void)
         CHECK(strcmp(tell(11, ": X S\" 66 EMIT\" 14 SEND ; X"), "B") == 0 && printed_from == 14, "and to the one across from it, which it is not wired to: \"%s\"", printed);
         CHECK(clock_of(10) > hera, "that went by a node in between");
     }
-    CHECK(strcmp(tell(10, "(LOST) @ ."), "0 ") == 0 && strcmp(tell(11, "(LOST) @ ."), "0 ") == 0 && strcmp(tell(14, "(LOST) @ ."), "0 ") == 0, "nothing was let go");
+    CHECK(strcmp(tell(10, "(LOST) @ ."), "0 ") == 0 && strcmp(tell(11, "(LOST) @ ."), "2 ") == 0 && strcmp(tell(14, "(LOST) @ ."), "0 ") == 0,
+          "nothing was let go but the two answers that came back to node 11, which did not wait for them: \"%s\"", printed);
 
     /* ---- they share the store (acceptance 3) ---- */
     step_limit = 30000000ul;
@@ -514,7 +515,7 @@ int main(void)
     CHECK(told(10, ": GO S\" W\" 12 SEND W ; GO"), "Hera sets node 12 writing and writes her own meanwhile: \"%s\"", printed);
     for (i = 0; i < 10 && common_dev[(12 + i) * V4_BLOCK_BYTES] == 'a' && common_dev[(22 + i) * V4_BLOCK_BYTES] == 'b'; i++) { }
     CHECK(i == 10, "all twenty blocks reached the store: the first that did not is %u", i);
-    CHECK(strcmp(tell(10, "(LOST) @ ."), "0 ") == 0 && strcmp(tell(12, "(LOST) @ ."), "0 ") == 0, "and no message was let go");
+    CHECK(strcmp(tell(10, "(LOST) @ ."), "1 ") == 0 && strcmp(tell(12, "(LOST) @ ."), "0 ") == 0, "and no message was let go but node 12's answer to Hera, who did not wait for it: \"%s\"", printed);
     CHECK(waiting(10) && waiting(11) && waiting(12) && waiting(13) && waiting(14), "all five are waiting at their ports again");
 
     /* ---- Hera kills a node by number, and tells the others it is gone (MESH.md 7b, 7d) ----