Support MC_AIGOD_CONFIG env var for multi-instance deployment

CONFIG_PATH now reads from MC_AIGOD_CONFIG env var, falling back
to /etc/mc_aigod_paper.json. Enables running multiple instances
with different configs (e.g. dev server with fine-tuned model).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

mc_aigod_paper.py

@@ -24,7 +24,7 @@ logging.basicConfig(
 )
 log = logging.getLogger(__name__)
 
-CONFIG_PATH = '/etc/mc_aigod_paper.json'
+CONFIG_PATH = os.environ.get('MC_AIGOD_CONFIG', '/etc/mc_aigod_paper.json')
 
 PRAY_PATTERNS = [
     re.compile(r'\[.*?\]: (?:\[Not Secure\] )?<(\w+)> [Pp]ray (.+)'),