refactor: switch Mumble voice to pymumble transport

asyncio's SSL memory-BIO transport silently drops voice packets even
though text works fine. pymumble uses blocking ssl.SSLSocket.send()
which reliably delivers voice data.

- Rewrite MumbleBot to use pymumble for connection, SSL, ping, and
  voice encoding/sending
- Bridge pymumble thread callbacks to asyncio via
  run_coroutine_threadsafe for text dispatch
- Voice via sound_output.add_sound(pcm) -- pymumble handles Opus
  encoding, packetization, and timing
- Remove custom protobuf codec, voice varint, and opus ctypes wrapper
- Add container patches for pymumble ssl.wrap_socket (Python 3.13) and
  opuslib find_library (musl/Alpine)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

patches/apply_pymumble_ssl.py

@@ -0,0 +1,45 @@
+"""Patch pymumble deps for Python 3.13+ / musl (Alpine).
+
+1. pymumble: ssl.wrap_socket was removed in 3.13
+2. opuslib: ctypes.util.find_library fails on musl-based distros
+"""
+
+import pathlib
+import sysconfig
+
+site = sysconfig.get_path("purelib")
+
+# -- pymumble: replace ssl.wrap_socket with SSLContext --
+p = pathlib.Path(f"{site}/pymumble_py3/mumble.py")
+src = p.read_text()
+
+old = """\
+        try:
+            self.control_socket = ssl.wrap_socket(std_sock, certfile=self.certfile, keyfile=self.keyfile, ssl_version=ssl.PROTOCOL_TLS)
+        except AttributeError:
+            self.control_socket = ssl.wrap_socket(std_sock, certfile=self.certfile, keyfile=self.keyfile, ssl_version=ssl.PROTOCOL_TLSv1)
+        try:"""
+
+new = """\
+        ctx = ssl.SSLContext(ssl.PROTOCOL_TLS_CLIENT)
+        ctx.check_hostname = False
+        ctx.verify_mode = ssl.CERT_NONE
+        if self.certfile:
+            ctx.load_cert_chain(certfile=self.certfile, keyfile=self.keyfile)
+        self.control_socket = ctx.wrap_socket(std_sock, server_hostname=self.host)
+        try:"""
+
+assert old in src, "pymumble ssl patch target not found"
+p.write_text(src.replace(old, new))
+print("pymumble ssl patch applied")
+
+# -- opuslib: find_library fails on musl, use direct CDLL fallback --
+p = pathlib.Path(f"{site}/opuslib/api/__init__.py")
+src = p.read_text()
+
+old_opus = "lib_location = find_library('opus')"
+new_opus = "lib_location = find_library('opus') or 'libopus.so.0'"
+
+assert old_opus in src, "opuslib find_library patch target not found"
+p.write_text(src.replace(old_opus, new_opus))
+print("opuslib musl patch applied")