fix(voice): guard e2ee_manager access when E2EE disabled (diagnostic mode)

voice.py

@@ -302,6 +302,8 @@ class VoiceSession:
             # The caller's track is subscribed during the wait; if no key is set when
             # the frame cryptor is first created it enters DEC_FAILED and drops all frames
             # even after the key is set later.
+            kp = None
+            if e2ee_opts is not None:
                 kp = self.lk_room.e2ee_manager.key_provider
                 kp.set_key(bot_identity, self._bot_key, 0)
                 logger.info("Set bot raw key for %s (%d bytes)", bot_identity, len(self._bot_key))
@@ -315,6 +317,8 @@ class VoiceSession:
                 elif self._caller_key:
                     kp.set_shared_key(_hkdf_derive(self._caller_key), 0)
                     logger.info("Early-set shared_key (pre-derived) caller key[0] (%d bytes)", 16)
+            else:
+                logger.info("E2EE disabled (diagnostic mode) — skipping key setup")
 
             # Element Call rotates its encryption key when bot joins the LiveKit room.
             # EC sends the new key via Matrix (Megolm-encrypted); nio sync will decrypt it
@@ -353,7 +357,7 @@ class VoiceSession:
             # Set shared_key with pre-derived AES key for caller decryption.
             # NOT using set_key() for caller — Rust HKDF may produce different result than EC's JS HKDF.
             # set_shared_key() stores key raw (no KDF applied) — we pre-derive in Python.
-            if self._caller_all_keys:
+            if kp is not None and self._caller_all_keys:
                 try:
                     for idx, base_k in sorted(self._caller_all_keys.items()):
                         derived = _hkdf_derive(base_k)
@@ -361,7 +365,7 @@ class VoiceSession:
                         logger.info("Set shared_key (pre-derived)[%d] (%d bytes)", idx, len(derived))
                 except Exception as e:
                     logger.warning("Failed to set caller shared_key: %s", e)
-            elif not self._caller_all_keys:
+            elif e2ee_opts is not None and not self._caller_all_keys:
                 logger.warning("No caller E2EE keys — incoming audio will be silence")
 
             if remote_identity: