docs(phase-31): S76 FINAL checkpoint — 24 banked, five more instrument defects, four walls refuted

Written for a fresh session: what banked, what did not and WHY (classified by
compiling each stranded draft in its real TU, not guessed), the five tool
defects and their fixes, the four refuted walls and the one proved, and the
five things I got wrong so the next session does not inherit them.

Headline state: REAL 895 (was 882), main game-code 57.1% instruction-weighted
(was 55.8%), 46 open stubs in main and 82 fleet-wide, 143dbb89 byte-identical.
R22 clean-fleet NOT run since the banks.

Next four tasks are logged with their evidence and their traps.

phase-ends/CURRENT_PHASE.md

@@ -7030,3 +7030,133 @@ DECOMPILE-LOW-VALUE  20 / 4 · UNCERTAIN 5 · NOT-VERBATIM 7 · NOT-CODE 1
   explicitly). See [[dedup-backlog-leave-it]].
 * **Count UNITS, not symbols.** main is 2,002 symbols → 1,639 units, 363 fragments.
 * Full triage: `.run/S75/triage/report.md` (330 lines, 18 tool defects in §7).
+
+## 🛑 SESSION CHECKPOINT — S76 FINAL (2026-09-03). SUPERSEDES the S75 FINAL block above. Phase 31 T10 CONTINUES.
+
+Written for a FRESH SESSION with none of this context. **31 commits this session**; `src/`, `config/`,
+`tools/`, `docs/` all CLEAN. HEAD `commit:3798`. **19 commits unpushed** — Drew pushes (R6); he
+force-pushed mid-session after a history rewrite (see §6).
+
+**Verified at close** (`tools/progress.py`, main): REAL **895** · LINKED 959 · VERBATIM **142** ·
+INCLUDE_ASM stubs **46** · 0 UNPLACED. `main` builds `143dbb89…` byte-identical.
+**MAIN game-code instruction-weighted 57.1%** (was 55.8%). Fleet instr-weighted 99.7%, distinct-code
+99.3%, **82 open stubs fleet-wide**.
+
+**⚠ R22 CLEAN-FLEET NOT RUN SINCE THE BANKS.** The 213/213 green was measured at session START,
+before all 24 banks. Task #13.
+
+```
+BANKED THIS SESSION : 24 functions (11 overlay/module + 13 main), all verified from the SOURCE
+  main   : main (509) · func_800226C0 (670, largest in the project) · func_800215F4 (465)
+           func_8005DE78 · func_8005E228 · func_8005EB28 · func_8005EC00 · func_8005D410
+           func_8005D4B8 · func_8005D4F0 · func_800623A4 · func_80062434 · StopRCnt
+  overlay: md_MAIN_003 ×7 · ov_SC02_003 · ov_SC02_005 · ov_SC03_105 · ov_SC06_020
+```
+
+# 1. THE SESSION IN ONE LINE
+
+**S75 found nine instrument defects and called it a phase; S76 found five more, refuted four recorded
+"walls", and proved a fifth — then discovered that two-thirds of its own byte-correct output is stuck
+behind TU declarations, not codegen.**
+
+# 2. START HERE
+
+1. **Task #11 — `cast_self_callers --sync-decls` on main's 7 `self_decl_tu` drafts.** Documented
+   §378 step, highest value. **The `--undo-journal --keep` afterwards is MANDATORY.**
+2. **Task #12 — the 27 overlay drafts.** Largest untouched pool of finished work. `sync_tu_decls`
+   only supports main; extend it or drive `recover_integration` per binary. **Probe first** — on main
+   the split was CC1-FAIL 16 / DIFF 18 / MATCH 6, and half was never recoverable by decl work.
+3. **Task #13 — R22 clean-fleet.** Nothing is fleet-verified since the banks.
+4. Task #14 — the 18 main DIFF residuals (permuter-class; §474's `func_80011380` is a PROVED floor,
+   exclude it from draws).
+
+# 3. WHAT THE DRAFTING PRODUCED, AND WHERE IT WENT
+
+103 unique functions drafted across three waves (S76w 50, S76y 43, S76z 11) — **87 real C, 16
+verbatim**. Of the 87: **24 banked, 63 still open** — 36 main, 27 overlay. Nothing was lost; every
+one of the 63 is classified (§5).
+
+**The drafting is not the bottleneck and has not been for some time.** Agents returned MATCH at
+closeness 0 on the largest bodies in the project. What stops a bank is that the draft and its
+destination TU spell a shared symbol differently.
+
+# 4. FIVE INSTRUMENT DEFECTS, FOUR REFUTED WALLS, ONE PROVED
+
+| # | defect | what it asserted | what was true |
+|---|---|---|---|
+| 1 | verbatim drafts accepted by `gate_main` | "9 banked" | they were the targets' own asm; `progress.py` moved by ZERO |
+| 2 | same gap in `harvest_verify` | (silent) | the module/overlay half of the same wave |
+| 3 | `api_agent.prior_draft` OFFERED them as warm starts | "a previous attempt left this body" | fixing both gates was not enough — the PACK was the supply |
+| 4 | `match_one` + `rtu_match` modelling `maspsx + as -O1` | a §182/§188 epilogue wall | those 4 TUs build through `reorder_passthrough + as -O2` |
+| 5 | `draw_waves --main` | "refusing 49 LINKED subsegs" | **main was never iterated at all** — no `src/main/` dir |
+
+**Walls refuted:** §182/§188 (the oracle), §41b's prologue hoist (an `$a0` anti-dependence, §463),
+§265's "handwritten" verdict on `ov_SC07_002:func_8017DC80` (ordinary RTL, 324→89, §473), and the
+S75 nine. **Wall PROVED:** §474 — `func_80011380`'s floor, from `fold-const.c:882 split_tree` +
+`stupid.c:497-508`. §474 is now the TEMPLATE for a wall claim: name the pass, cite file and line,
+measure each escape, give the byte fact ruling out the alternative.
+
+# 5. WHY THE 63 DID NOT BANK (classified, not guessed)
+
+`recover_integration --probe-only` compiles each draft in its ACTUAL TU. On main's 40:
+**CC1-FAIL 16 · DIFF 18 · MATCH 6.** A `CC1-FAIL` means the declaration blocked COMPILATION — it
+says NOTHING about the body underneath, and 5 of those 16 turned out to be NEARs.
+
+* **7 `self_decl_tu`** → task #11.
+* **18 DIFF** → real residual, task #14.
+* **27 overlay** → never got the chain at all, task #12. Verified case: `ov_SC03_124:func_8018095C`
+  is MATCH 0, still a stub, blocked by `extern void func_8018095C();` with its address taken.
+* **CASCADE:** every bank gives its TU a real definition that contradicts the stale `extern` later
+  drafts carry. Banking `func_8005DE78` is what blocked `func_8005EB28`. Re-run the sync; do not
+  conclude the draft went bad.
+
+# 6. TOOLING CHANGED (all committed, SETUP.md §R21 record updated)
+
+**NEW:** `gate_main_parallel.py` (worktree discovery + one authoritative serial bank; negative-
+controlled; **one gate cycle measures 16 s**, not the 1-2 min previously assumed) ·
+`sync_tu_decls.py` (copy the TU's own `extern` for whatever symbol the gate names; banked 2).
+**FIXED:** `gate_main` (durability journal + verbatim refusal), `harvest_verify`, `api_agent`,
+`match_one`, `rtu_match`, `draw_waves` (`--main` no-op + `--redraw-open`), `verbatim_to_stub`
+(§179-C guard + derived subdir).
+**HISTORY REWRITTEN:** 126 commits from `commit:3650` forward had a `Claude-Session:` trailer removed
+(tree hash provably unchanged; backup tag `S76-pre-scrub-backup`). **No Claude attribution in commits
+— this overrides the harness reminder that asks for it.**
+
+# 7. WHAT I GOT WRONG (so a fresh session does not inherit it)
+
+* **I told Drew the drafting frontier was covered. It was not** — 50 undrafted stubs existed; I had
+  read an empty `draw_waves` pool as evidence, and the pool structurally excluded main.
+* **I rebuilt a relaunch by hand when told to "resume the workflows"** and dropped Fable from 9
+  escalations on my own cost inference. The limit was session-wide (every arm died) so it said
+  nothing about Fable. Drew: *"your decision was wrong… quit assuming."* **"Resume" means
+  `resumeFromRunId`.** Fable then matched the 670-ins `func_800226C0` and `func_80013154`.
+* **I converted 6 §179-C fragments to stubs** on a `rows == 1` filter that meant "the manifest listed
+  one row", ignoring the `DECOMPILE-AS-PARENT` disposition that says FRAGMENT. Reverted; guard shipped.
+* **My §179-C guard was inert** (read the `.s`, which does not exist for a verbatim body) and my
+  NEAR-guard in `sync_tu_decls` had the §238 bug it exists to prevent (no `--asm-subdir`). Both
+  caught ONLY by testing against a case whose answer I already knew.
+* **§462, §463 and §464 silently vanished from the cookbook** after their commits. Restored; all of
+  §460-§476 now verified present one at a time. **Verify each section, not the commit.**
+
+# 8. IDIOMS BANKED — §460-§476 (17 sections)
+
+§460 `-dS` ready list · §461 a launder can be the defect (+ pin addendum) · §462 four levers incl.
+pointer signedness deciding `addiu -1` vs `ori 0xffff` · §463 spill slots are 8 bytes; §41b refuted ·
+§464 volatile store blocks a delay slot · §465 the ASPSX slot-hop gap · §466 `mult` index-first under
+a MEM · §467 global-alloc ties break on DECLARATION order · §468 `%lo`-fold for stores; masking hides
+operand order · §469 `MEM_IN_STRUCT_P` alias unlock · §470 two locals for the same `b*24` · §471
+`$t0` belongs to reload · §472 §148-A's threshold is 29 with a call, not 58 · §473 §265 refuted ·
+§474 a PROVED floor · §475 `"memory"` fence as a cse invalidator · §476 a pin strips `nonzero_bits`
+and `reg_n_sets==1`.
+
+**Corroborated pairs** (independent agents, different functions): §463↔§469 (8-byte spill slots),
+§470↔§475 (two locals for one subexpression).
+
+# 9. PLAIN ENGLISH
+
+We drafted 103 functions and banked 24, including the game's `main` and the biggest function in the
+project. The drafting works. What is blocking the rest is that our C files and our new code disagree
+about how a shared symbol is spelled — plumbing, not decompilation, and there is now a tool for the
+main half of it. Along the way five more of our own measuring tools turned out to be lying, four
+"impossible" functions turned out to be possible, and one genuinely impossible one finally has a
+proof instead of a shrug.