cleanup: remove Godot-era test data, formats/, dead proto reader and duplicates

- test/: bgfx/Godot render goldens and compare shots nothing reads any more;
  the Granny oracle result m2-numeric.json moves to oracle/
- formats/: only the .spt sniffer was still linked; it moves into
  platform/SpeedTreeLib, the rest and tools/map_probe go
- bgm/ duplicated Client/BGM byte for byte; tools/root archived root scripts
  that root.epk already holds; extension/src/proto had no build reference
- GEMINI.md duplicated AGENTS.md

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

oracle/run-diff-suite.sh

@@ -1,12 +1,12 @@
 #!/usr/bin/env bash
-# M2 门禁·主：对测试资产集跑 oracle dump + oracle_diff，汇总 test/m2-numeric.json。
+# M2 门禁·主：对测试资产集跑 oracle dump + oracle_diff，汇总 oracle/m2-numeric.json。
 # 前置：oracle/build-wine.sh 已产出 oracle.exe；WINEPREFIX 已 init（见 RUNBOOK.md）；
 #       oracle_diff 已构建（cmake -B build-tools -DMT_BUILD_TOOLS=ON）。
 set -uo pipefail
 cd "$(dirname "$0")/.."
 REPO="$(pwd)"
 ASSETS="$(cd "${MT_ASSETS:-$REPO/assets}" && pwd)"
-DUMPS="$REPO/test/oracle_dumps"
+DUMPS="$REPO/build/oracle_dumps"
 DIFF=""
 for c in "$REPO/build-tools/tools/oracle_diff" "$REPO/build/tools/oracle_diff"; do
     [ -x "$c" ] && DIFF="$c" && break
@@ -72,7 +72,7 @@ wait
 
 # ── 2. diff + 汇总 ─────────────────────────────────────────────────────
 echo "== oracle_diff =="
-JSON="$REPO/test/m2-numeric.json"
+JSON="$REPO/oracle/m2-numeric.json"
 {
   echo '{'
   echo '  "granny": "2.9.12.0",'