docs(config): surface telegram.reactions in DEFAULT_CONFIG (#17028)

The telegram.reactions key was already wired up (gateway/config.py bridges
it to TELEGRAM_REACTIONS at startup) but was undocumented and missing from
DEFAULT_CONFIG, so users had no way to discover it. Add it with the
existing off-by-default behavior preserved.

No behavior change — runtime default stays False.

Co-authored-by: teknium1 <teknium@users.noreply.github.com>

hermes_cli/config.py

@@ -932,6 +932,7 @@ DEFAULT_CONFIG = {
 
     # Telegram platform settings (gateway mode)
     "telegram": {
+        "reactions": False,            # Add 👀/✅/❌ reactions to messages during processing
         "channel_prompts": {},         # Per-chat/topic ephemeral system prompts (topics inherit from parent group)
     },