fix: WebSocket proxy drops text frames — receive_bytes() silently fails on auth token

terminal.js sends the ttyd auth token as a TEXT WebSocket frame. The proxy's
client_to_ttyd() called receive_bytes() which fails silently on text frames,
swallows the exception, and exits — auth never reached ttyd, ttyd never
started streaming, resulting in permanent black screen and reconnect loop.

Fix: use receive() and dispatch on message type, handling both bytes and text.

muxplex/tests/test_ws_proxy.py

@@ -0,0 +1,28 @@
+"""
+Regression tests for the WebSocket proxy in muxplex/main.py.
+"""
+
+import inspect
+
+from muxplex.main import terminal_ws_proxy
+
+
+def test_terminal_ws_proxy_does_not_use_receive_bytes():
+    """Regression: receive_bytes() silently drops TEXT frames (like the ttyd auth token).
+
+    terminal.js sends {"AuthToken": ""} as a TEXT WebSocket frame. The original
+    proxy used receive_bytes() which fails on text frames, swallowed the exception,
+    and exited — meaning ttyd never received the auth token, never started
+    streaming, resulting in a permanent black screen and reconnect loop.
+
+    The proxy MUST use receive() and dispatch on message type to handle both
+    binary and text frames correctly.
+    """
+    source = inspect.getsource(terminal_ws_proxy)
+    assert "receive_bytes" not in source, (
+        "client_to_ttyd must not use receive_bytes() — silently drops text frames "
+        'like the ttyd auth token {"AuthToken": ""}'
+    )
+    assert ".receive()" in source, (
+        "client_to_ttyd must use receive() to handle both text and binary frames"
+    )