Correct the voice_gate_ratio tuning direction

A higher ratio raises the loudness gate, so it rejects more audio rather than less. The config guidance claimed the opposite; pin the direction with a test.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

config.example.yaml

@@ -58,8 +58,9 @@ wake_word:
   silence_ms: 800            # end-of-utterance silence
   voice_gate_ratio: 3.0      # how much louder than the background a frame must be to count as
                              # the user talking — lets recording end while your own speakers play
-                             # music (Silero rates music as speech). 0 = off, raise if commands
-                             # get cut off, lower if music keeps the recorder running.
+                             # music (Silero rates music as speech). 0 = off. Higher is stricter:
+                             # raise it if music keeps the recorder running, lower it if quiet
+                             # commands get cut off.
 
 mcp:
   servers_config: "mcp_servers.json"