fix(config): update stale comment from bird CLI to twitter-cli (#284)

The project has migrated from bird to twitter-cli, but this inline
comment still referenced the old name. Consistent with the fix in #282.

agent_reach/config.py

@@ -21,7 +21,7 @@ class Config:
     # Feature → required config keys
     FEATURE_REQUIREMENTS = {
         "exa_search": ["exa_api_key"],
-        "twitter_xreach": ["twitter_auth_token", "twitter_ct0"],  # legacy key name; used by bird CLI
+        "twitter_xreach": ["twitter_auth_token", "twitter_ct0"],  # legacy key name; used by twitter-cli
         "groq_whisper": ["groq_api_key"],
         "github_token": ["github_token"],
     }