feat(v4.0.0): Hera kills a node by number and tells the others it is gone

Hera keeps a table of the nodes she has had born, number and place.
KILL ( n -- ): she asks the kernel to remove node n, forgets her own way
to it, and sends GONE about it to every other node in the table.  A node
she never had born, herself, or one she has killed already is an error
that says so, and nothing is removed.  v3's word and meaning; v3's takes
a name, and a mesh node has a number.

test_host_unit.c, 74 checks: Hera kills node 14 while node 12 is blocked
writing to it, and what 12 then sends there is refused; node 12 waits on
node 13, stuck in a loop and not its neighbour, and the wait ends Node
gone when Hera kills 13; Hera waits on node 12, stuck, and a line typed at
the console ends her wait Interrupted and then kills 12.

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

capsules/v4/hera.4th

@@ -32,6 +32,20 @@ VARIABLE (KID)  VARIABLE (KID#)  VARIABLE (KIDP)
   BEGIN PAD CAPSULE-LINE DUP 0< 0= WHILE PAD SWAP (TELL) REPEAT
   DROP ;
 Block 8002
+( The nodes this one has had born: for each its number and   )
+( its place in the fabric.  Sixteen at most.                 )
+CREATE (KIDS) 32 ALLOT   VARIABLE (KIDS#)   0 (KIDS#) !
+: (KID@) ( i -- addr ) 2 * (KIDS) + ;
+: (NOTE) ( number place -- )
+  (KIDS#) @ 16 < IF
+    (KIDS#) @ (KID@) SWAP OVER 1+ ! !  1 (KIDS#) +!
+  ELSE DROP DROP THEN ;
+( which of them has that number: its place in the list, or -1 )
+: (WHICH) ( number -- i | -1 )
+  -1 SWAP  (KIDS#) @ DUP IF 0 DO
+    DUP I (KID@) @ = IF SWAP DROP I SWAP THEN
+  LOOP ELSE DROP THEN DROP ;
+Block 8003
 ( who it is, where its printing goes, and that everything    )
 ( not told of goes by its port 2, where this node is         )
 : (WHO) ( -- )
@@ -48,9 +62,10 @@ Block 8002
   (NUCLEUS)
   (KID#) @ (KIDP) @ ROUTE  (KID#) @ (KIDP) @ NEIGHBOUR  (WHO)
   S" v4:forth79.4th" (LINES)
-Block 8003
+Block 8004
   S" (SEAL)" (TELL)
   (KID) @ (KID#) @ NODE-PARITY
+  (KID#) @ (KID) @ (NOTE)
   (KID) @ ;
 ( Two outer nodes are joined: port 3 of X to port 4 of Y,    )
 ( and each is told the other is there.                       )
@@ -63,7 +78,7 @@ VARIABLE (XP)  VARIABLE (XN)  VARIABLE (YP)  VARIABLE (YN)
 : (JOIN) ( -- )
   (XP) @ 3 (YP) @ 4 NODE-WIRE 0= IF (FAIL) THEN
   (YN) @ 3 (XN) @ (SAY)  (XN) @ 4 (YN) @ (SAY) ;
-Block 8004
+Block 8005
 ( n --    A UNIT: four outer nodes, n+1 to n+4, on ports 2   )
 ( to 5 of this one, and joined in a square: 1-2, 2-4, 4-3,   )
 ( 3-1.  The corners across from each other are not wired:    )
@@ -78,3 +93,19 @@ VARIABLE (P1)  VARIABLE (P2)  VARIABLE (P3)  VARIABLE (P4)
   (P2) @ 2 (N) (X)  (P4) @ 4 (N) (Y)  (JOIN)
   (P4) @ 4 (N) (X)  (P3) @ 3 (N) (Y)  (JOIN)
   (P3) @ 3 (N) (X)  (P1) @ 1 (N) (Y)  (JOIN) ;
+Block 8006
+( n --    KILL: node n is removed, whatever it was doing.    )
+( This node forgets the way to it, and every other node it   )
+( has had born is told that n is gone: each forgets its way  )
+( to n, and one that is waiting for n's answer stops.        )
+( docs/v4.0.0/MESH.md 7b.5.  As v3's KILL, by number.        )
+: (UNLIST) ( i -- )
+  (KIDS#) @ 1- DUP (KIDS#) !  (KID@) DUP @ SWAP 1+ @
+  ROT (KID@) SWAP OVER 1+ ! ! ;
+: KILL ( n -- )
+  DUP (WHICH) DUP 0< IF
+    DROP DROP ." KILL: no such node" CR  -1 NODE-ERROR ! THEN
+  DUP (KID@) 1+ @ NODE-KILL  (UNLIST)
+  DUP NO-ROUTE
+  (KIDS#) @ DUP IF 0 DO DUP I (KID@) @ GONE LOOP ELSE DROP THEN
+  DROP ;