PC port: phase 2 — handoff for D51 session: findings D50/D51, rewritten HANDOFF + research §G/§H

- §F/D50: Plan B execution record (emit pass, plumbing, lang/font fixups,
  legal-screen UB, texCopyGdls byte proof)
- §F/D51: current blocker — import_texture_i8 via main-DL G_TEXRECT lazy
  tile-0 upload; GE opcode space facts (non-F3DEX numbering, G_TEXRECT=0xE4)
- HANDOFF.md rewritten: Task 1 = live-breakpoint gdb recipe for D51,
  Task 2 = pixel assert + soak, Task 3 = Tbg_*_stanZ backgrounds
- AGENTS.md phase status updated (D43/Plan B closed, D51 open)

AGENTS.md

@@ -48,6 +48,6 @@ Run `/linkcheck` for this sweep. Record new findings in `docs/PCPortResearch.md`
 - **Compile+link milestone:** all ~235 TUs compile and `ge007.x86_64.exe` links clean (`ninja ge007 -k 0`, 236/236). Findings D7–D17 in `docs/PCPortResearch.md` §11; asset stubs in `port/src/assetstubs.c`, fast3d no-ops in `port/src/gfxstub.c` (delete when real fast3d lands).
 - **Phase 1 (boot to window):** done — ROM loads/validates/maps at cart base 0x10000000 (`romdata.c`), SDL2 window + GL clear loop (`video.c`), absolute asset symbols from `scripts/gen_romassets.py` → `port/src/romassets_<r>.s` (findings D18–D23).
 - **Phase 1.5 (boot to first frame):** DONE — boot chain complete AND real frames render (`[NOTE] frame N rendered in … us`). D34–D42 closed the blockers on top of D31–D33: ANIM_DATA lvalues, music seq-table ABI+endianness, music-heap sizing, libaudio bank-tree re-layout, implicit-declaration prototype shim (D38), Globalimagetable rebasing + true segment size (D39), ModelHitEntry pool sizing (D40), cross-thread GL context release (D41), rsp task-settings toggle (D42). ROM dump verified against the No-Intro good dump (byte-identical, header CRCs re-checked — `tools_pc/romverify.c`).
-- **Phase 2 (rendering):** IN PROGRESS — fast3d integrated + first frames render; current blocker is **D43** (model-file loading ABI mismatch: N64-layout ROM model files read as 8-byte-pointer PC structs → D37-style re-layout). **D43 status:** all 512 model files validated; buffer sizing finalized by the D46 overlap-safety analysis; step-2 mechanical game-code edits APPLIED + committed (ecefffdb); **D47 closed every open converter question** — compaction state values, G_VTX encoding, opcode-aware remap rule, vertex formats — spec implemented + validated 512/512 by `tools_pc/d43_convert.py` (max D_PC = 0xB7E0, ratio ≤ 1.31). **D48 review re-plan:** the old "port d43_convert.py 1:1 to C" task is discarded — that script does not emit bytes, and **Plan B (offline pre-conversion)** is now the default: Python emit pass → `data/pcmodels-<region>/` RZ sidecars served via a port-layer `hw_address`/`rom_size` table patch (no C converter; full mechanics in §F/D48). **D49 review PASSED** — all 8 D48 checklist items CONFIRMED against code + ROM (§F/D49): RZ format, memcpy DMA path, table chokepoint, obInit timing, buffer fit (worst-case P_final 0x16F74 vs 0x24C400 bank), reload hazard + pending one-line reset, per-region sidecars (EU=465 files; no JP ROM candidate yet), emission spec complete (fresh C probe: no record-size drift; added the bswap16-record-scalars rule). Next session EXECUTES Plan B (HANDOFF Task 2); fallback Plan A = D47.13 C converter with the corrected staging guard (D48.4: `D_N64 + D_PC ≤ avail`). All 23 d43_*.py scripts moved from gitignored build-pc/ to tracked `tools_pc/`. Recurring sub-task: ABI/layout fixes per the D32 procedure (§H) as more asset types are first touched (PD's `preprocess/` module already solves most of them; prefer the offline pattern for format work — D48).
+- **Phase 2 (rendering):** IN PROGRESS — fast3d integrated + real frames render. **Plan B EXECUTED (D50, committed):** all 512 NTSC model files converted offline by `tools_pc/d43_emit.py` → `data/pcmodels-ntsc-final/pcmodels.bin` + manifest.csv (single concatenated RZ image; regenerate per region with the script — sidecars are gitignored), served through the existing load path via a port-layer table patch (`port/src/pcmodels.c`, romdata cart-extension, one-shot `pcmodelsPatchTable()` + poolRemaining reset hook in `load_object_fill_header`); runtime C fixups for language-bank BE offset tables + font re-layout (D50.3/D50.4); legal-screen UB seed (D50.5); **D50.6 fixed the first model-render crash** — `texCopyGdls` copied only w0 of each 16-byte Gfx slot on PC (the union's trailing `long long` is 8 bytes), leaving stale mempool w1s in the compacted GDLs; byte-proven against PlegalpageZ, fixed with a full-slot copy under #ifdef PORT. Model GDLs now execute to completion (PlegalpageZ sub-DLs). **Current blocker D51:** SIGSEGV in `import_texture_i8` via a main-DL G_TEXRECT lazy tile-0 upload (frame 5) — GE opcode space decoded (G_TEXRECT=0xE4/0xE5, non-F3DEX numbering; see §F/D51); investigation recipe in HANDOFF Task 1. Next: D51 → pixel-assert soak (PPM dump + pixcount still unbuilt) → next asset type (Tbg_*_stanZ backgrounds, same offline pattern; PD `preprocess/filebg.c` reference). Recurring sub-task: ABI/layout fixes per the D32 procedure (§H) as more asset types are first touched (PD's `preprocess/` module already solves most of them; prefer the offline pattern for format work — D48; full-struct Gfx copies on PC — D50.6).
 - **Phase 3 (audio + input):** libaudio → SDL — largely copy-and-adapt from PD (`mixer.c` 722 lines vs our 31-line stub; `input.c` SDL_GameController backend; §2.4); decide the ASP strategy (C2: `aspMain*` dummies in `ucode.c`).
 - **Phase 4 (saves + polish):** file-backed EEPROM — build on PD's `fs.c` (file-backed save dir); PFS/motor already no-op stubs.