M-29 docs: race-to-release plan, audio deferred, B2 Depot texture diagnostic

HANDOFF: M-29 session summary + the 3-track plan (A=playtest gate,
B=audio DEFERRED, C=solo quick wins in priority order).
BRIEF-B2-depot-textures.md: captured evidence + leading hypothesis that
the Depot roof garbage is mostly BACKLOG B1 (missing filtering/mips),
not a decode bug; decode path audited clean.

docs/BRIEF-B2-depot-textures.md

@@ -0,0 +1,65 @@
+# BRIEF — B2: Depot (-level_30) wrong-colour / garbage textures
+
+M-29 diagnostic pass. **Not fixed.** Evidence captured, leading hypothesis
+recorded. Companion: `docs/BACKLOG.md` B1/B2, `docs/SMALL-FIXES.md` C-section.
+
+## Symptom (captured)
+
+`-level_30`, opening loading-bay area, `GE_PCDUMP` frames ~700-1150
+(camera panning up toward the roof):
+
+- The **ceiling / roof surface** renders as bright blue with a dense green
+  speckle and radial "light-ray" streaks emanating from a point. On N64 this
+  is a dark, low-contrast corrugated roof.
+- Walls (green wall panels right, tan crates left) look approximately
+  correct — mild green tint at most.
+- HUD ammo digits mirrored = D116, unrelated.
+
+Frames: `ppm/frame_0007..1150` this session (regenerate with
+`GE_PCDUMP="700-1600:150" ./build-pc/ge007.x86_64.exe -level_30`).
+
+## Leading hypothesis (revised M-29): this is mostly B1, not a decode bug
+
+The radial-ray + sparkle pattern is the **classic grazing-angle aliasing**
+signature of a high-frequency texture sampled with point/bilinear filtering
+and no working LOD/mipmap chain. The ceiling is at a very shallow angle to
+the camera in these frames — exactly where N64 3-point + LOD filtering
+suppresses shimmer and our fast3d path does not (see BACKLOG B1: "whole game
+has an interlaced/shimmering look"; `port/fast3d/gfx_pc.cpp` mip handling is
+stubbed — `gfx_lod_tile_offset` / "for now just ignore smaller mips" at
+~1540, and D107 notes fast3d fabricates a crop when detail textures are off).
+
+**Decode path was audited and looks correct:**
+- `gfx_dp_load_tlut` byteswaps entries (`PD_BE16`), `palette_to_rgba32`
+  decodes RGBA16 5551 and IA16 correctly, `rdp.palette_fmt` is set from
+  `other_mode_h & (3<<G_MDSFT_TEXTLUT)` (line ~2389).
+- `import_texture_rgba16` / `ci4` / `ci8` decode textbook-correct, BE reads.
+- D72 already disabled the PD normal-derived texgen for GE, so the streaks
+  are not env-mapping.
+
+Nothing in the decode path obviously produces "blue + green speckle".
+
+## Next diagnostic step (for a focused session)
+
+1. **Probe the ceiling draw:** in `gfx_pc.cpp` `import_texture` / the tri
+   setup, `GE_DTEX=1`-gate a log of `{orig_addr, fmt, siz, palette_index,
+   line_size_bytes, width, height, cms/cmt, other_mode_h & TEXTFILT, tex_lod}`
+   for the first ~200 unique textures on `-level_30`. Identify which entry is
+   the ceiling (large, tiled, grazing).
+2. If its `fmt/siz` and data look sane → confirm B1: the fix is proper
+   trilinear + a real mip chain (or an N64 3-point-filter emulation shader),
+   per BACKLOG B1 "MVP: one good default filtering mode". Do B1 first, then
+   re-shoot this frame; B2 likely collapses into it.
+3. If the data is garbage (wrong TMEM offset, wrong decompressed RZ section)
+   → it's a real decode/addressing bug: check `line_size_bytes` vs
+   `full_image_line_size_bytes` (the `SUPPORT_CHECK` at
+   `import_texture_rgba16:657` is *commented out* with a TODO about garbage
+   `full_image_line_size_bytes`), and the RZ section offset from
+   `rzipGetSomething()` in `src/game/image.c`.
+
+## Risk / scope
+
+B1 (filtering + mips) is a medium fast3d task with a clear reference (PD port,
+Nightdive 3-point emu). It is the highest-leverage single graphics fix —
+addresses the game-wide shimmer complaint AND (hypothesis) most of B2. Do it
+as its own focused effort, not inline.

docs/HANDOFF.md

@@ -401,6 +401,43 @@ Start, exactly like the retail game.** No crashes, no hangs. 10 commits
 - The D75 front-end / cutscene 3D-model family (D148/D149) is now the
   biggest *visible* gap but is cosmetic — below crashes.
 
+## Done this session (M-29) — race-to-release plan; audio DEFERRED; 2 commits
+
+**Direction (user, M-29):** ship the solo campaign start→finish, fastest.
+Three tracks: A = full 21-level playtest (release gate, user batch-reports a
+defect list from a solo playthrough); B = **audio DEFERRED** — ship silent,
+add sound post-launch (`docs/AUDIO-PLAN.md` stays valid for later, do NOT
+start it); C = solo quick wins, priority: **B2 textures** > B3 blood-stain
+converter > B5/B6 menu input > C2 (D75 models) > C4 (D148 cutscene) >
+C1 (mirrored HUD — user unsure it's worth it). Full plan +
+`docs/SMALL-FIXES.md` mapping in the `m29-release-push` memory.
+
+- **`0bd0ceec`** — aim sensitivity (SMALL-FIXES B4 / BACKLOG B3):
+  `Input.MouseAimSpeed` default 50→25 (overshot), new `Input.AimBand` knob
+  (5..40, def 20). Port-only, `ge007.ini`-tunable. Needs playtest feel check.
+- **`bf5e4d3d`** — file-backed EEPROM saves (BACKLOG B5 / Phase 4):
+  `osEeprom*` in `port/src/libultra.c` now back `data/ge007.eep` (2 KB /
+  16Kbit, lazy-load + write-through, PD pattern). `osEepromProbe` →
+  `EEPROM_TYPE_16K`. Verified: game writes the file (checksum @blk 0 +
+  save_data @blk 4), `-level_09` unregressed, persists across runs.
+  Campaign progress now survives quit.
+- **SMALL-FIXES B1 (D74 wrap block) — DEFERRED.** The in-place one-liner
+  (`G_TX_CLAMP` test + `[t]` index) activates never-run code and boot-crashes
+  `-level_09` (0 frames). Left inert with a NOTE in `gfx_pc.cpp`. Needs the
+  hoist-out-of-vertex-loop rework + per-level visual check.
+- **B2 (Depot wrong textures) — DIAGNOSED, not fixed.** `docs/BRIEF-B2-depot-
+  textures.md`. Captured `-level_30` frames: the roof/ceiling renders as
+  blue + green speckle + radial rays. Decode path (TLUT bswap,
+  `palette_to_rgba32`, `import_texture_*`) audited clean. **Leading
+  hypothesis: this is mostly BACKLOG B1** (grazing-angle aliasing from
+  missing N64 3-point filtering + a stubbed mip chain), not a decode bug.
+  Recommendation: do B1 (filtering + mips, PD/Nightdive reference) as its own
+  focused effort — highest-leverage single graphics fix, likely collapses B2
+  into it. Next diagnostic = `GE_DTEX` probe of the ceiling texture params.
+- **D153 reminder cost real time this session:** back-to-back `-level_09`
+  runs during builds boot-crash under machine thrash; only regression-test on
+  a settled machine (clean run = 600+ frames fine).
+
 ## Done this session (M-28) — D150 (watch page crash) + D151 (watch text blank)
 
 - **D150** (`src/str.c`, `#ifdef PORT`, uncommitted) — user found a crash