PC port: Phase 1.5 — fix langInit decompression (D31), start D32 ABI layout

- D31 (resolved): replace GE's gzip-1.2.4 inflate with real-zlib
  decompressdata() in port/src/rzdecomp.c; exclude src/game/decompress.c +
  zlib.c from the PC build. Root cause: struct huft is 8B on MIPS but 16B on
  x86-64, overflowing load_resource's fixed 0x2100 buffer and clobbering its
  frame/retaddr on the first file load. mainThread now boots past all language
  files into bossInitMainthreadData().

- D32 (in progress): ROM-serialized structs with 32-bit pointer fields
  misalign when read as 64-bit pointers. Part A done: ModelAnimation's
  bitDescriptors/bitStream are now u32 (N64 layout preserved) with casts at the
  two use sites in model.c. Part B (load-time rebase in expand_ani_table_entries)
  is open — see docs §F/D32 + §H.

- Docs: D31 resolved, D32 recorded (A done / B open), Phase 1.5 added, new §H
  handoff section. AGENTS.md: refined non-negotiable #2 to "game logic is
  unmodified" with a narrow ABI/layout exception; refreshed phase status.

AGENTS.md

@@ -4,12 +4,12 @@
 
 - `n64decomp/007`: WIP decompilation of GoldenEye 007 (N64), byte-matches US/EU/JP ROMs.
 - Active work: **PC port** modelled on the Perfect Dark PC port (same Rare "Indy" engine family).
-- **Read `docs/PCPortResearch.md` first** — architecture, GE-specific RSP deltas, phased plan, and review findings (A1–C2 in §11).
+- **Read `docs/PCPortResearch.md` first** — architecture, GE-specific RSP deltas, phased plan, and review findings (A1–D32 in §11; current handoff + plan in §H).
 
 ## Non-negotiables
 
 1. **N64 build untouched.** `Makefile`, `tools/`, `rsp/`, `ld/` belong to the N64 build. Never modify them for the PC port.
-2. **Game code compiles unmodified.** `src/game/*.c` + the curated `src/*.c` list compile as-is for the host. All N64 hardware dependencies are satisfied by the `port/` layer. If a game file seems to need a change, stop — the fix belongs in `port/`.
+2. **Game logic is unmodified.** The decomp's control flow and behavior are ground truth for 1:1 fidelity — never change them. All N64 *hardware* dependencies are satisfied by the `port/` layer; if a game file seems to need a behavioral change, stop — the fix belongs in `port/`. **Narrow exception (ABI/layout only):** the 32→64-bit transition forces a small class of mechanical, semantics-preserving edits that cannot be isolated in `port/` — chiefly pointer-width reconciliation in ROM-serialized structs (a struct with a 32-bit-pointer field misaligns when read as 64-bit). These follow the PD ground-truth pattern (store the embedded address as `u32`, cast to a real pointer at the use site), change no logic or behavior, and are each documented in `docs/PCPortResearch.md` §F/D3x. No other game-code edits are permitted.
 3. **Region macros mirror the Makefile.** `CMakeLists.txt` `REGION_DEFS` must match the N64 Makefile's per-region macro set exactly (finding A1). Divergence = silent branch divergence + link failures.
 4. **`src/libultrare/Makefile.libultrare` is ground truth** for original-vs-Rare libultra files (finding B3). The PC build compiles: `libultra/audio`, `libultrare/audio` (drvrNew/env/reverb), `libultra/gu`, and `libultrare/io/vitbl.c` only. All other `io/` + `os/` files are excluded and shimmed in `port/src/libultra.c`.
 5. **`rsp/graphics/gmain.s` is the RSP ground truth** — the authoritative reference for which GBI commands GE emits (modified fast3d, 1545 lines). We do not run it on PC; `port/fast3d/` replaces it. Use it to validate the software RSP's command decoding and the custom CC/RM modes.
@@ -46,7 +46,7 @@ Run `/linkcheck` for this sweep. Record new findings in `docs/PCPortResearch.md`
 - **Phase 0 (scaffolding):** done, committed.
 - **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 2 (rendering):** bring in PD fast3d (replaces `port/src/gfxstub.c`), verify custom CC/RM modes against `gmain.s`, port the scheduler; replace asset stubs with ROM-backed data (D16).
-- **Phase 2 (rendering):** bring in PD fast3d, verify custom CC/RM modes against `gmain.s`, port the scheduler.
+- **Phase 1.5 (boot to first frame):** IN PROGRESS — mainThread runs through `bossInitMainthreadData()`; D31 (langInit file-load SIGSEGV) fixed via real-zlib decompression (`port/src/rzdecomp.c`, replaces the excluded `src/game/decompress.c`+`zlib.c`). Current blocker is **D32** (ROM-struct pointer-width): Part A (u32 layout in `ModelAnimation`) done, Part B (load-time rebase in `expand_ani_table_entries`) open. Recurring sub-task: ABI/layout fixes per the D32 procedure (§H) as more asset loading is reached.
+- **Phase 2 (rendering):** bring in PD fast3d (replaces `port/src/gfxstub.c`), verify custom CC/RM modes against `gmain.s`, port the scheduler; replace asset stubs with ROM-backed data (D16). Assumes ABI-clean data loading from Phase 1.5.
 - **Phase 3 (audio + input):** libaudio → SDL; decide the ASP strategy (C2: `aspMain*` dummies in `ucode.c`).
 - **Phase 4 (saves + polish):** file-backed EEPROM; PFS/motor already no-op stubs.