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/host_map.h

@@ -95,12 +95,17 @@
 #define OUT_HDR      (BUF0_W - 112)             /* the seven words of a message this node is putting on a wire */
 #define W_NEED       (BUF0_W - 105)             /* the wait for room: how many cells, */
 #define W_PORT       (BUF0_W - 104)             /*   and on which port's wire */
-#define P_WAY        (BUF0_W - 103)             /* the port a message being passed on goes by */
+#define P_WAY        (BUF0_W - 103)             /* the port a message being passed on goes by, */
+#define P_NEED       (BUF0_W - 100)             /*   and the cells it needs there */
+#define H_PORT       (BUF0_W - 99)              /* the port of the first message left on its wire for want of room on this pass; -1: none */
+#define H_NEED       (BUF0_W - 98)              /*   the cells it needs there */
+#define H_MASK       (BUF0_W - 97)              /*   and a bit for each port something was left for */
 #define A_SELF       (BUF0_W - 102)             /* 1: a message of this node's own, for the node it waits on, came back and was let go here */
 #define SEND_PTR     (BUF0_W - 101)             /* where the next word of a text being made ready to send goes */
 #define OUT_TEXT     (OUT_W - 64)               /* what was printed, four characters to a cell, as it goes on the wire: 64 cells */
 #define SEND_TEXT    (OUT_W - 400)              /* the text of a message SEND is putting, four characters to a cell: 256 cells */
-/* FREE, plain memory: BUF0_W - 8; - 32 .. - 21; - 100 .. - 97; - 115 .. - 113; and OUT_W - 144 .. OUT_W - 65.  They and
+/* FREE, plain memory: BUF0_W - 8; - 32 .. - 21; - 122 .. - 113; BUF0_W - 144 .. - 141 (what a flush makes zero after
+ * a full output buffer); and OUT_W - 144 .. OUT_W - 65.  They and
  * the cells above held the messages waiting, the refusals owed and what went with them (MESH.md 7a, 7b), which a
  * node no longer keeps. */
 #define AWAIT_FROM   (BUF0_W - 39)              /* the node whose word of how text ended is waited for */
@@ -228,6 +233,10 @@ static int host_load(v4_text *tx, v4_node *n, const char *const *files, unsigned
     v4_text_constant(tx, "(W-NEED)", W_NEED);
     v4_text_constant(tx, "(W-PORT)", W_PORT);
     v4_text_constant(tx, "(P-WAY)", P_WAY);
+    v4_text_constant(tx, "(P-NEED)", P_NEED);
+    v4_text_constant(tx, "(H-PORT)", H_PORT);
+    v4_text_constant(tx, "(H-NEED)", H_NEED);
+    v4_text_constant(tx, "(H-MASK)", H_MASK);
     v4_text_constant(tx, "(A-SELF)", A_SELF);
     v4_text_constant(tx, "(SEND^)", SEND_PTR);
     v4_text_constant(tx, "(OUT-TEXT)", OUT_TEXT);