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/start_server.sh

@@ -0,0 +1,53 @@
+#!/bin/sh
+set -eu
+
+server_root=${MT40250_ROOT:-/usr/metin2}
+runtime="$server_root/server"
+pid_file="$server_root/.mt40250-pids"
+if [ "$(uname -s)" != "FreeBSD" ]; then
+	echo "start_server.sh: 40250 runtime is FreeBSD-only" >&2
+	exit 2
+fi
+if [ ! -x "$runtime/db/db" ] || [ ! -x "$runtime/auth/auth" ]; then
+	echo "start_server.sh: run prepare_runtime.sh first" >&2
+	exit 2
+fi
+if [ -f "$pid_file" ]; then
+	echo "start_server.sh: $pid_file exists; stop the existing server first" >&2
+	exit 2
+fi
+
+launch() {
+	name=$1
+	dir=$2
+	bin=$3
+	if [ ! -x "$dir/$bin" ]; then
+		echo "start_server.sh: missing $dir/$bin" >&2
+		exit 2
+	fi
+	(
+		cd "$dir"
+		exec "./$bin"
+	) >> "$dir/console.log" 2>&1 &
+	pid=$!
+	echo "$pid $name" >> "$pid_file"
+	echo "started $name pid=$pid"
+}
+
+: > "$pid_file"
+launch db "$runtime/db" db
+sleep "${MT40250_DB_WAIT_SECONDS:-2}"
+launch auth "$runtime/auth" auth
+
+channels=${MT40250_CHANNELS:-"1 2 3 4"}
+for channel in $channels; do
+	for node in first game1 game2; do
+		launch "channel${channel}/${node}" "$runtime/channel${channel}/${node}" game
+	done
+done
+
+if [ "${MT40250_START_GAME99:-1}" = "1" ]; then
+	launch game99 "$runtime/game99" game
+fi
+
+echo "40250 server started; logs are under $runtime/*/console.log"