docs(discord): document DAVE defaults and decrypt recovery

docs/channels/discord.md

@@ -936,6 +936,8 @@ Notes:
 - `voice.tts` overrides `messages.tts` for voice playback only.
 - Voice is enabled by default; set `channels.discord.voice.enabled=false` to disable it.
 - `voice.daveEncryption` and `voice.decryptionFailureTolerance` pass through to `@discordjs/voice` join options.
+- `@discordjs/voice` defaults are `daveEncryption=true` and `decryptionFailureTolerance=24` if unset.
+- OpenClaw also watches receive decrypt failures and auto-recovers by leaving/rejoining the voice channel after repeated failures in a short window.
 - If receive logs repeatedly show `DecryptionFailed(UnencryptedWhenPassthroughDisabled)`, this may be the upstream `@discordjs/voice` receive bug tracked in [discord.js #11419](https://github.com/discordjs/discord.js/issues/11419).
 
 ## Voice messages
@@ -1012,6 +1014,18 @@ openclaw logs --follow
     If you set `channels.discord.allowBots=true`, use strict mention and allowlist rules to avoid loop behavior.
 
   </Accordion>
+
+  <Accordion title="Voice STT drops with DecryptionFailed(...)">
+
+    - keep OpenClaw current (`openclaw update`) so the Discord voice receive recovery logic is present
+    - confirm `channels.discord.voice.daveEncryption=true` (default)
+    - start from `channels.discord.voice.decryptionFailureTolerance=24` (upstream default) and tune only if needed
+    - watch logs for:
+      - `discord voice: DAVE decrypt failures detected`
+      - `discord voice: repeated decrypt failures; attempting rejoin`
+    - if failures continue after automatic rejoin, collect logs and compare against [discord.js #11419](https://github.com/discordjs/discord.js/issues/11419)
+
+  </Accordion>
 </AccordionGroup>
 
 ## Configuration reference pointers