feat(v4): word accounts at call -- the word ID in the header, the kernel's records, the Stadium charged per tick (#189)

ENGINE step 4 Phase 2 (plan docs/v4.0.0/plans/2026-11-13-engine-step4-phase2-word-accounts.md). Rulings,
Captain Bob 2026-11-13: "ID field in the header"; "Per heartbeat tick"; the ACL "All of it in Phase 4".

- The word ID, at xt-4 before the flags (ENGINE.md 3b). The system's words are numbered as they are
  assembled, by a new directive, #id, (and #ids, the count), in the C assembler (text.c) and in the
  machine ROM's (capsules/v4/rom), which counts in the system's own (NEXT-ID). (HEADER) numbers later
  words; FORGET gives back the IDs it frees, always the newest; COLD resets to (BOOT-ID); (SEAL) records
  it. All 313 system headers carry the cell.
- The kernel's records (v4/mesh.h): (TELL-DEFINED) and (TELL-FORGOTTEN), requests -19/-20 on port 0,
  which the kernel puts in (WORD-DEFINED)/(WORD-FORGOTTEN) when it seals a node, and reads the system's
  own words once. A bit per address marks a word's xt (calls into the ROM or headerless code are not
  words); at call, the bit test and a count. v4_mesh_charge hands the owner the calls since.
- The Stadium: stadium_words_charge -- N calls as N of stadium_word_dispatch's dispatches, shared by calls
  when the reservoir is short; sk_v4.c charges every node's words at the tick beside its opcodes, and
  stadium_word_forget before an ID is used again.
- Tests first: test_text.c, test_host_dict.c, test_host_quit.c (numbering, FORGET, COLD),
  test_mesh_boot.c (44 checks), kernel/tests/test_stadium_words.c; qemu_session.py: Hera's words
  admitted after POST.
- amd64: Stadium words: promotions=141 after POST, CONSERVED; POST 539/539; word_count=377;
  dict_hash 0xa854ba15b437d288 (the new cell); the boot 142 s against Phase 1's 153 s.
- v4 test, test-32: all pass; v4-checks: 80 programs under the sanitizers, 0 failures; the hosted
  builds alike. docs/reference/v4-dictionary.tsv: the two new words; FABRIC-3 XLVIII.24.

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

docs/reference/v4-dictionary.tsv

@@ -18,6 +18,8 @@
 (REFUSED)	( -- addr )	Variable: a count of the messages that came back to this node, refused.
 (S")	( -- baddr u )	The run time of S": leave the address and length of the string compiled after the call.
 (SEAL)	( -- )	What is in the dictionary now is the system: COLD returns to it and FORGET will not go below it.
+(TELL-DEFINED)	( xt -- )	Tells the kernel that an entry has been made, with its code at xt (request -19 on port 0). The kernel puts it in (WORD-DEFINED) when it seals a node.
+(TELL-FORGOTTEN)	( w -- )	Tells the kernel that every entry from word address w up has gone (request -20 on port 0). The kernel puts it in (WORD-FORGOTTEN) when it seals a node.
 (UD)	( -- addr )	Variable: U/MOD's divisor while it divides (forth79.4th).
 (WORD-DEFINED)	( -- addr )	Variable: the hook told when an entry is made, with the xt its code will be at.
 (WORD-FORGOTTEN)	( -- addr )	Variable: the hook told when entries are forgotten, with the word address they went from.