docs(timing): log GTE per-command stall + dirty-interp muldiv parity

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

ACCURACY_BURNDOWN.md

@@ -110,7 +110,13 @@ observe added to the recompiler so ANY block leader is anchorable on both backen
 - [ ] **Instruction-fetch / I-cache** — ruler #1 shows the residual: Beetle 84 on
   cold-line hits (I-cache refill) vs native flat 56. Next component. Beetle
   ReadInstruction (+0 hit / +4 KSEG1 / +3+refill miss).
-- [ ] GTE per-command cycles — Beetle gte.cpp GTE_Instruction; DuckStation; psx-spx.
+- [x] **GTE per-command cycles — DONE, validated EXACT** (commit ec1fd76).
+  CPUState.gte_ts_done armed in gte_execute (cost-1 table verified from beetle
+  gte.cpp op returns; AVSZ4=5 not 6); any COP2 reg access stalls to it; both
+  emitters + interp. Ruler #2 gte_rtps +15 / gte_nclip +8 == Beetle. FMV no-reg.
+- [x] **Mult/div stall — also completed to the dirty-RAM interpreter** (commit
+  75d5d1a): backend parity (interp was charging 0 for mult/div). By-construction
+  + no-regression (no interp-path ruler yet — see below).
 - [ ] Instruction-fetch / I-cache timing — Beetle ReadInstruction (+0 hit / +4 KSEG1
   / +3+refill miss). Ruler's 56→84 cold spread is the I-cache line-refill transient.
 - [ ] **HW test-ROM ruler (#2)** — Amidog CPU/GTE timing ROMs for hand-crafted

FAITHFUL_TIMING_PLAN.md

@@ -213,6 +213,17 @@ on a fixed region -> next.
 
 ## 5. Status / Log (update every session)
 
+- **2026-06-27 (GTE per-command completion-stall — VALIDATED EXACT):** Modeled
+  GTE (COP2) command latency + stall-on-COP2-access. New CPUState.gte_ts_done;
+  a GTE command arms it (now + cost-1, serializing back-to-back ops); any COP2
+  reg access (MFC2/CFC2/MTC2/CTC2/LWC2/SWC2) stalls to it. Cost table
+  (psx_cycles.c) transcribed+verified from beetle gte.cpp op returns (note
+  AVSZ4=5 not the psx-spx-doc's 6). Set armed in the shared gte_execute (both
+  backends); stall emitted at every COP2 reg-access site in both emitters + the
+  interp (offset cancels like muldiv). Added gte_rtps/gte_nclip loops to ruler
+  #2: native +15/+8 == Beetle +15/+8 EXACT; all other components unchanged;
+  Tomba2 boots to FMV no-regression. Commit ec1fd76. Required regen. UNPUSHED.
+
 - **2026-06-27 (dirty-interp mult/div completion-stall — backend parity):**
   Completed the mult/div stall to the SECOND backend. The dirty-RAM interpreter
   (Tomba2 overlays) charged 0 for mult/div while the compiled emitters already