v9: multi-destination tunnel support (parspack, mequ, alipi)

Server:
- /tunnel/<dest> routes: parspack (185.208.174.152:22),
  mequ (188.213.68.133:2022), alipi (10.66.66.2:22)
- /tunnel without dest defaults to parspack

Client (tunnel.py):
- --destination / -d flag to pick target
- Lists available destinations in --help

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

chat.py

@@ -25,8 +25,12 @@ import html
 import urllib.parse
 
 PORT = 9999
-VERSION = "8"
-TUNNEL_TARGET = ("185.208.174.152", 22)
+VERSION = "9"
+TUNNEL_TARGETS = {
+    "parspack": ("185.208.174.152", 22),
+    "mequ":     ("188.213.68.133", 2022),
+    "alipi":    ("10.66.66.2", 22),
+}
 MAX_FILE_SIZE = 1 * 1024 * 1024       # 1 MB per file
 MAX_TOTAL_STORAGE = 50 * 1024 * 1024  # 50 MB total
 
@@ -380,10 +384,10 @@ def ws_make_frame(opcode, data):
     return frame + data
 
 
-async def handle_ws_tunnel(ws_reader, ws_writer):
-    """Bridge WebSocket frames <-> raw TCP to TUNNEL_TARGET."""
+async def handle_ws_tunnel(ws_reader, ws_writer, target):
+    """Bridge WebSocket frames <-> raw TCP to target (host, port)."""
     try:
-        ssh_reader, ssh_writer = await asyncio.open_connection(*TUNNEL_TARGET)
+        ssh_reader, ssh_writer = await asyncio.open_connection(*target)
     except Exception as e:
         ws_writer.write(ws_make_frame(0x8, struct.pack("!H", 1011) + str(e).encode()[:123]))
         await ws_writer.drain()
@@ -569,8 +573,22 @@ async def handle_http(reader, writer, first_line):
         writer.close()
         return
 
-    # GET /tunnel — WebSocket upgrade for SSH tunnel
-    if method == "GET" and path == "/tunnel":
+    # GET /tunnel/<dest> — WebSocket upgrade for SSH tunnel
+    if method == "GET" and path.startswith("/tunnel"):
+        # Parse destination: /tunnel/parspack, /tunnel/mequ, or /tunnel (default: parspack)
+        parts = path.strip("/").split("/")
+        dest_name = parts[1] if len(parts) > 1 else "parspack"
+        target = TUNNEL_TARGETS.get(dest_name)
+        if not target:
+            names = ", ".join(TUNNEL_TARGETS.keys())
+            err = f"Unknown destination '{dest_name}'. Available: {names}".encode()
+            writer.write(b"HTTP/1.1 404 Not Found\r\n")
+            writer.write(f"Content-Length: {len(err)}\r\n".encode())
+            writer.write(b"\r\n")
+            writer.write(err)
+            await writer.drain()
+            writer.close()
+            return
         ws_key = headers.get("sec-websocket-key", "")
         if not ws_key:
             writer.write(b"HTTP/1.1 400 Bad Request\r\nContent-Length: 0\r\n\r\n")
@@ -586,7 +604,7 @@ async def handle_http(reader, writer, first_line):
                       f"Sec-WebSocket-Accept: {accept}\r\n"
                       f"\r\n".encode())
         await writer.drain()
-        await handle_ws_tunnel(reader, writer)
+        await handle_ws_tunnel(reader, writer, target)
         return
 
     # 404