feat(assets): solve asset resolution (SYS4INI per-scene section manifest)

resId -> files[section_base(scene) + resId]. SYS4INI's file list is
sectioned, one per scene (SCxxxx.BIN + its cross-archive asset manifest);
file_number is the index within the section. Unified for set-texture,
play-bgm, play-voice. Fully static/general -> no per-scene capture.

- tools/parse_sys4ini.py: SYS4INI (S4IC422, LZSS) -> build/asset-index.json
- tools/resolve_asset.py: sections + (scene,resId) resolver -> build/asset-sections.json
- validated: 97% structural, SC0000 17/17 vs Frida, 586/595 captured loads
- opcodes.toml: set-texture/create/draw-texture, play-bgm/voice enriched (frida-grounded)
- Frida tooling (capture_load_order all-archive, correlate_scope, ...) + vm0 --settex
- docs: asset-resolution-re (step2 SOLVED), global-memory-re (shelved), tools-reference

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

docs/PROJECT-STRUCTURE.md

@@ -54,7 +54,10 @@ S:\Game Hacking\Eushully\Himegari\           ← workspace root (three siblings)
     │   └── opcode-leads.json, small-script-listings.md
     │
     ├── docs/                                 all documentation
-    │   ├── PROJECT-STRUCTURE.md                this file
+    │   ├── PROJECT-STRUCTURE.md                this file (where things live)
+    │   ├── tools-reference.md                  every tool: purpose, usage, I/O (operational companion)
+    │   ├── asset-resolution-re.md              resId→file RE (graphics/audio); asset-index steering
+    │   ├── global-memory-re.md                 runtime global observation RE (SHELVED; future starting point)
     │   ├── remake-architecture-and-roadmap.md  THE direction doc (phases A–E)
     │   ├── phase-a-slice-plan.md               the current slice (A0/A1/A2)
     │   ├── vm-mapping-plan.md                  the phased decode plan