layout: restructure into src/ tests/ android/ scripts/ tools/

- extension/src/{port,platform,codepage} -> src/; native_render -> src/host
  (+ dxt, shaders/); libgr2 -> src/gr2; extension/third_party -> third_party
- extension/tests -> tests/port, libgr2/tests -> tests/gr2
- android-native -> android (build.sh, push-client.sh moved in)
- script -> scripts; tools/40250 -> tools/server; oracle -> tools/granny-oracle;
  perf tools -> tools/perf
- all build trees under build/ (native, release, android, port-gate)
- xrender:: CMake aliases -> mt::; port-map ledger impl paths rewritten

No code changes. ctest 15/15, port_gate macos+android PASS, port_map check 0 errors.

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

tools/server/prepare_runtime.sh

@@ -0,0 +1,17 @@
+#!/bin/sh
+set -eu
+
+server_root=${MT40250_ROOT:-/usr/metin2}
+runtime="$server_root/server"
+if [ "$(uname -s)" != "FreeBSD" ]; then
+	echo "prepare_runtime.sh: runtime binaries are FreeBSD-only" >&2
+	exit 2
+fi
+if [ ! -x "$runtime/install.sh" ]; then
+	echo "prepare_runtime.sh: missing $runtime/install.sh" >&2
+	exit 2
+fi
+
+cd "$runtime"
+sh ./install.sh
+echo "40250 runtime links and log/core directories ready under $runtime"