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/capsule/core.v4

@@ -14,6 +14,7 @@
 \    1 Negative count        2 Not a number        3 Number too long
 \    4 Not a character       5 Dictionary full     6 Name missing
 \    7 Control structure mismatch     8 Control structures too deep
+\    9 Shift count out of range
 \   -1 the word has printed its own message
 
 macro SWAP   over push push drop pop pop   endmacro