stage-4: discord bot minimal with channel/admin management

Discord.py bot with slash commands (/ping, /help, /setup, /channel, /admin), PID file, graceful shutdown. 30 new tests (119 total).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/main.py

@@ -0,0 +1,69 @@
+"""Echo Core — main entry point."""
+
+import asyncio
+import logging
+import os
+import signal
+import sys
+from pathlib import Path
+
+from src.config import load_config
+from src.secrets import get_secret
+from src.adapters.discord_bot import create_bot
+
+PROJECT_ROOT = Path(__file__).resolve().parent.parent
+PID_FILE = PROJECT_ROOT / "echo-core.pid"
+LOG_DIR = PROJECT_ROOT / "logs"
+
+
+def setup_logging():
+    LOG_DIR.mkdir(parents=True, exist_ok=True)
+    logging.basicConfig(
+        level=logging.INFO,
+        format="%(asctime)s [%(levelname)s] %(name)s: %(message)s",
+        handlers=[
+            logging.FileHandler(LOG_DIR / "echo-core.log"),
+            logging.StreamHandler(sys.stderr),
+        ],
+    )
+
+
+def main():
+    setup_logging()
+    logger = logging.getLogger("echo-core")
+
+    token = get_secret("discord_token")
+    if not token:
+        logger.error(
+            "discord_token not found in keyring. "
+            "Run: python cli.py secrets set discord_token"
+        )
+        sys.exit(1)
+
+    config = load_config()
+    client = create_bot(config)
+
+    # PID file
+    PID_FILE.write_text(str(os.getpid()))
+
+    # Signal handlers for graceful shutdown
+    loop = asyncio.new_event_loop()
+
+    def handle_signal(sig, frame):
+        logger.info("Received signal %s, shutting down...", sig)
+        loop.create_task(client.close())
+
+    signal.signal(signal.SIGTERM, handle_signal)
+    signal.signal(signal.SIGINT, handle_signal)
+
+    try:
+        loop.run_until_complete(client.start(token))
+    except KeyboardInterrupt:
+        loop.run_until_complete(client.close())
+    finally:
+        PID_FILE.unlink(missing_ok=True)
+        logger.info("Echo Core shut down.")
+
+
+if __name__ == "__main__":
+    main()