feat(v4.0.0): 48 more words at the prompt (words.v4)

capsule/words.v4: the stack, comparison, shift, double, mixed and string
words whose definitions DECOMPOSITION.md already gives and the mesh-node
tests execute, now in the host node's vocabulary:

  2SWAP 2OVER 2ROT 2>R 2R> 2R@ 2@ 2! -! 0<> 0> <> <= >= U< U> ABS MAX MIN
  WITHIN LSHIFT RSHIFT D- DABS D0= D0< D= D2* D2/ D< DMAX DMIN M+ M-
  CMOVE> MOVE FILL ERASE BLANK -TRAILING COMPARE SEARCH SCAN SKIP
  ?TERMINAL TRUE FALSE INVERT NOP

- A shift count that is negative or as large as the cell is an error, as
  in v3 (code 9, "Shift count out of range").
- tests/test_host_quit.c: 36 sessions from the prompt that are
  transcripts of the v3 binary, and the cases where v4 keeps the standard
  (MOVE in cells; M+ and M- with the double low cell first).

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

v4/tests/host_map.h

@@ -53,6 +53,7 @@
 #define SBUF_W       (TOP - 540)                /* 64 cells for the tests' own strings */
 #define HBUF_W       (SVARS - 16)               /* the hold buffer: 16 cells = 64 bytes */
 #define HEND         ((HBUF_W + 16) * 4)
+#define XVARS        (HBUF_W - 4)               /* (X): words.v4, 4 cells */
 #define WBUF         (WBUF_W * 4)
 #define TIB          (TIB_W * 4)
 #define PAD          (PAD_W * 4)
@@ -112,6 +113,8 @@ static int host_load(v4_text *tx, v4_node *n, const char *const *files, unsigned
     v4_text_constant(tx, "(F)", FVARS);
     v4_text_constant(tx, "(S)", SVARS);
     v4_text_constant(tx, "(W)", WVARS);
+    v4_text_constant(tx, "(X)", XVARS);
+    v4_text_constant(tx, "MAX-INT", (v4_cell)(V4_MSB - 1u));
     v4_text_constant(tx, "HLD", HLD);
     v4_text_constant(tx, "HEND", HEND);
     v4_text_constant(tx, "-HFLOOR", -(HEND - 62));