feat(v4.0.0): CASE, ['], S", WORDS, FORGET and FENCE

- compile.v4: CASE OF ENDOF ENDCASE, as v3 (they nest; a word out of
  place is a control structure mismatch); ['] and [LITERAL].
- quit.v4: S" and its run-time word; at the prompt the text is copied to
  PAD.
- capsule/system.v4: WORDS and VLIST; FORGET (FORTH-79), which gives the
  space back and will not remove a word below FENCE -- the capsule's own
  words -- where v3's FORGET DUP succeeds.
- tests/test_host_quit.c: ten more transcripts of the v3 binary, and
  nesting, the fence and the listing.

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

v4/capsule/quit.v4

@@ -96,6 +96,7 @@ header ABORT
   -if POS  drop  2 jump (REPL)
   POS: -1 + if M1  -1 + if M2  -1 + if M3  -1 + if M4
        -1 + if M5  -1 + if M6  -1 + if M7  -1 + if M8  -1 + if M9
+       -1 + if M10
        drop  2 jump (REPL)
   M1: drop  $6167654E (EMIT4) $65766974 (EMIT4) $756F6320 (EMIT4) $746E (EMIT4) CR  2 jump (REPL)
   M2: drop  $20746F4E (EMIT4) $756E2061 (EMIT4) $7265626D (EMIT4) CR  2 jump (REPL)
@@ -106,6 +107,7 @@ header ABORT
   M7: drop  $746E6F43 (EMIT4) $206C6F72 (EMIT4) $75727473 (EMIT4) $72757463 (EMIT4) $696D2065 (EMIT4) $74616D73 (EMIT4) $6863 (EMIT4) CR  2 jump (REPL)
   M8: drop  $746E6F43 (EMIT4) $206C6F72 (EMIT4) $75727473 (EMIT4) $72757463 (EMIT4) $74207365 (EMIT4) $64206F6F (EMIT4) $706565 (EMIT4) CR  2 jump (REPL)
   M9: drop  $66696853 (EMIT4) $6F632074 (EMIT4) $20746E75 (EMIT4) $2074756F (EMIT4) $7220666F (EMIT4) $65676E61 (EMIT4) CR  2 jump (REPL)
+  M10: drop  $746F7250 (EMIT4) $65746365 (EMIT4) $6F772064 (EMIT4) $6472 (EMIT4) CR  2 jump (REPL)
 
 \ The table the loader gives the node: six words, one for each kind of
 \ fault in the node's order, each a jump.  A jump fills its word, so they
@@ -170,3 +172,20 @@ header ABORT" immediate
   NOW: drop  if NO
   drop  WBUF COUNT TYPE  CR  jump ABORT
   NO: drop ;
+
+\ The run time of S" : leave the address and length of the string after the
+\ call, and go on after it.
+: (S")
+  pop 4*  dup C@                             \ baddr n
+  over over + 4/ 1 + push                    \ the cell after the last character
+  push 1 + pop ;                             \ baddr+1 n
+
+\ ( -- baddr u )   S" text"  as v3.  In a definition the text is compiled
+\ into it.  At the prompt it is copied to PAD, where it stays until PAD is
+\ used again: WORD's buffer is overwritten by the very next word of the line.
+header S" immediate
+: S-QUOTE
+  34 (PARSE) drop
+  STATE a! @ if NOW
+  drop  &(S") (CALL,)  jump (STRING,)
+  NOW: drop  WBUF+1 PAD WBUF C@ CMOVE  PAD WBUF jump C@