feat: enhance decompilation and server management scripts

- Introduced `decompile.sh` to automate the decompilation process, including downloading `MinecraftDecompiler.jar` and server.jar for specified Minecraft versions.
- Added `mc-rcon.sh` for sending RCON commands to a Minecraft server, improving server management capabilities.
- Created `mcc-env.sh` to provide helper functions for managing Minecraft servers, including starting, stopping, and sending commands.
- Implemented `start-server.sh` to launch a Minecraft server in a tmux session with a named pipe for stdin, facilitating easier command input.
- Updated `README.md` to reflect new tools and usage instructions for decompiling and server management.

These changes streamline the workflow for adapting to new Minecraft versions and enhance the overall development experience.

tools/mc-rcon.sh

@@ -0,0 +1,46 @@
+#!/bin/bash
+# Send an RCON command to a Minecraft server
+# Usage: mc-rcon.sh <command> [port] [password]
+set -euo pipefail
+
+CMD="${1:?Usage: mc-rcon.sh <command> [port] [password]}"
+PORT="${2:-25575}"
+PW="${3:-test123}"
+
+python3 -c "
+import socket, struct, sys
+
+s = socket.socket()
+s.settimeout(5)
+try:
+    s.connect(('localhost', $PORT))
+except Exception as e:
+    print(f'Connection failed: {e}', file=sys.stderr)
+    sys.exit(1)
+
+def send(req_id, pkt_type, body):
+    body = body.encode()
+    s.send(struct.pack('<iii', 10 + len(body), req_id, pkt_type) + body + b'\x00\x00')
+
+def recv():
+    length = struct.unpack('<i', s.recv(4))[0]
+    data = b''
+    while len(data) < length:
+        data += s.recv(length - len(data))
+    return data
+
+send(1, 3, '$PW')
+r = recv()
+rid = struct.unpack('<i', r[:4])[0]
+if rid == -1:
+    print('Auth failed', file=sys.stderr)
+    s.close()
+    sys.exit(1)
+
+send(2, 2, \"\"\"$CMD\"\"\")
+r = recv()
+body = r[8:-2].decode(errors='replace')
+if body:
+    print(body)
+s.close()
+"