feat(v4): every word but the ten is called, so it can be checked

Plan 2026-10-20 (ENGINE step 4), Task A2, for #189. Captain Bob,
2026-11-13: "The ten"; "Accept it".

- compile.f18 (COMPILE,): a word is copied in line only when it is flagged
  in-line and compile-only (24) -- the ten that work on the return stack,
  >R R> R@ I J LEAVE and the later UNLOOP 2>R 2R> 2R@. Every other word,
  in-line ones too, is a call the hook at `call` sees.
- EXECUTE calls the xt: `call xt` (opcode 3, slot 0) and a ; in (EXEC),
  run. INTERPRET runs a word by (GO): `call xt` and `jump (IL)` in
  (RUNX), entered by a jump, at the old return-stack depth.
- host_map.h: (EXEC) BUF0_W-22, (RUNX) BUF0_W-115, from what was free.
- Its cost, accepted: one return entry at the bottom of a chain (30 deep
  from the prompt, not 31) and one per explicit EXECUTE while its word
  runs; the hosted boot +2.4% (2.917 s to 2.987 s), instructions +0.4%.
- Tests first (logs/20261113-045122/a2): inline_words_are_called,
  residue_stays_inline, execute_passes_the_hook, rstack_kept_across_call,
  abandoned_definition_not_called -- 3 of 1096 failed before. The depth
  checks moved to the new figures; SEE shows the calls; two layout checks
  use in-line test words; 2>R 2R@ 2R> checked in test_host_quit.
- DECOMPOSITION.md EXECUTE, the plan's A2 and rulings, FABRIC-3 XLVIII.22.

Suite: test, test-32 99 programs 0 failures; v4-checks 79 under the
sanitizers 0 failures, the hosted builds alike; hosted POST 539/539.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017RzZgrf7V7Zk2iczBXDRbm

docs/v4.0.0/DECOMPOSITION.md

@@ -723,7 +723,7 @@ it, `xt + 1`; for any other word the parameter field is the code itself.
 | Word | Fate | Notes |
 | --- | --- | --- |
 | `(` `\` | CC | `(` is `41 WORD drop`; `\` is `SPAN @ >IN !`. In `v4/capsule/input.v4` under the names `PAREN` and `BACKSLASH`. Executed on the golden model's host node (2026-10-04). |
-| `EXECUTE` | CAP | `push ;` (tail-jumps to the xt; the xt returns to `EXECUTE`'s caller). Executed on the golden model's host node (2026-10-04). |
+| `EXECUTE` | CAP | ~~`push ;` (tail-jumps to the xt; the xt returns to `EXECUTE`'s caller). Executed on the golden model's host node (2026-10-04).~~ **2026-11-13 (#189, ruled 2026-10-20: "`EXECUTE` calls the xt"):** a `call xt` instruction word -- opcode 3 in slot 0, the address in the 27 bits below -- is put in `(EXEC)` with a `;` after it, and run; the xt returns to the `;`, which returns to `EXECUTE`'s caller, and the hook at `call` sees it. It costs one return entry while the xt runs (Captain Bob: "Accept it"). The interpreter runs a word the same way, by `(GO)`, whose second cell jumps back into its loop, at no cost in return entries. |
 | `NOP` | OP | `nop` |
 | `QUIT` | CC | FORTH-79; source in `v4/capsule/quit.v4`. Clears the return stack, sets execution mode, returns control to the terminal; no message. It is the prompt: after a new line it prints `ok> `, reads a line with `QUERY`, clears `NODE-ERROR`, runs `INTERPRET`, prints ` ok` — or, if `NODE-ERROR` is set, ends any definition that was open and prints ` ERROR` — and goes round again, for as long as the node runs. The text is v3's. The line is not sent back; the terminal shows what is typed. It empties the return stack first, by a store to `RSTACK-DEPTH` (D-16), so it works from however deep, with the return stack full. The data stack is left alone. A definition open when `QUIT` runs is ended and stays hidden. Executed on the golden model's host node (2026-10-04): the node is started at `QUIT`, fed characters and its output read, including 16 sessions recorded from the v3 binary. v3's `QUIT` goes on with the rest of the line and cannot be compiled into a definition. |
 | `ABORT` | CC | FORTH-79; source in `v4/capsule/quit.v4`. As `QUIT`, and it empties the data stack too (a store to `DSTACK-DEPTH`, D-16); the line it stops ends with ` ok`, as v3. Executed on the golden model's host node (2026-10-04), from six calls down and from inside two loops, forty times over, including transcripts of the v3 binary. |