make TSSBOT/start_bot.py a real Discord bot and reuse SREBOT venv (#1227)

- TSSBOT/start_bot.py: replace the print-and-idle stub with a minimal
  discord.py Client (commands.Bot with default+message_content intents).
  Loads TSSBOT/.env via python-dotenv, reads DISCORD_KEY, logs on_ready,
  handles SIGTERM/SIGINT cleanly. Aborts with a clear error if the token
  is missing instead of silently exit-looping.

- TSSBOT/ecosystem.config.js: switch the default interpreter from system
  python3 to SREBOT's venv (../SREBOT/.venv/bin/python). Both bots share
  BOTS/SHARED and the same baseline deps (discord.py, dotenv, …); split
  into a dedicated TSSBOT/.venv only when the dependency sets diverge.

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

start_bot.py

@@ -1,8 +1,9 @@
 #!/usr/bin/env python3
-"""Entry point for TSSBOT. Skeleton — idles until BOT/botscript.py is wired."""
+"""Entry point for TSSBOT. Connects to Discord and idles until commands land."""
+import logging
+import os
 import signal
 import sys
-import time
 from pathlib import Path
 
 # Make TSSBOT root and BOTS/SHARED importable.
@@ -10,15 +11,42 @@ _HERE = Path(__file__).resolve().parent
 sys.path.insert(0, str(_HERE))
 sys.path.insert(0, str(_HERE.parent / "SHARED"))
 
+import discord
+from discord.ext import commands
+from dotenv import load_dotenv
+
+load_dotenv(dotenv_path=_HERE / ".env")
+
+logging.basicConfig(
+    level=logging.INFO,
+    format="[%(asctime)s] [%(levelname)s] [tssbot] %(message)s",
+    datefmt="%Y-%m-%d %H:%M:%S",
+)
+log = logging.getLogger("tssbot")
+
 
 def _handle_signal(signum, _frame):
-    print(f"[tssbot] received signal {signum}, exiting")
+    log.info(f"received signal {signum}, exiting")
     sys.exit(0)
 
 
+TOKEN = os.environ.get("DISCORD_KEY", "").strip()
+
+intents = discord.Intents.default()
+intents.message_content = True
+bot = commands.Bot(command_prefix="!", intents=intents)
+
+
+@bot.event
+async def on_ready():
+    log.info(f"logged in as {bot.user} (id={bot.user.id if bot.user else '?'})")
+    log.info(f"connected to {len(bot.guilds)} guild(s)")
+
+
 if __name__ == "__main__":
     signal.signal(signal.SIGTERM, _handle_signal)
     signal.signal(signal.SIGINT, _handle_signal)
-    print("[tssbot] skeleton booted — replace with real bot once BOT/botscript.py exists")
-    while True:
-        time.sleep(60)
+    if not TOKEN:
+        log.error("DISCORD_KEY not set in TSSBOT/.env — aborting")
+        sys.exit(1)
+    bot.run(TOKEN, log_handler=None)