Apply conversation bot improvements (proto-improvements)

Diff vs working-copy baseline = exactly this session's bot edits:
- constants.py: env-var config, safe JSON loading, optional-dependency
  guards, env->netrc token resolution, API_SHARED_KEY + service_headers()
- communication_subroutine.py: queue get(timeout) + Empty handling,
  daemon threads, cooperative stop_event, inbound _authorize_request()
- bot.py: single asyncio event loop with cooperative shutdown
- music_functions / radio_commands / librarian_commands: send
  X-Conjurer-Api-Key on internal HTTP calls via service_headers()

Musician runtime data overlay dropped; conjurer_musician/.gitignore now
keeps generated playlists/mp3 out of the repo. The 1+2+3 musician code
port already lives in the base conjurer_musician.

Depends on #9: must merge after restructure/working-copy-root.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

bot.py

@@ -5,6 +5,7 @@
 """
 Module of a python bot named Conjurer - used to work on BDSM discord servers.
 """
+import asyncio
 import logging
 
 # *=========================================== Standard Library Imports
@@ -82,22 +83,52 @@ async def on_ready():
     logger.info("All systems: operational")
 
 
+# *=========================================== Runtime orchestration
+# The legacy bootstrap used two bare threads (client.run + comm_subroutine) and
+# joined them, which made a clean shutdown impossible.  We now drive everything
+# from a single asyncio loop: the Flask comm layer still runs in its own
+# threads (via asyncio.to_thread) but is steered through a shared stop_event so
+# the bot can stop both halves cooperatively.
+
+
+async def _run_comm_subroutine(stop_event: threading.Event) -> None:
+    """Run the blocking comm subroutine in a worker thread."""
+    await asyncio.to_thread(comm_subroutine, stop_event)
+
+
+async def _run_bot(token: str, shutdown_event: asyncio.Event) -> None:
+    """Start the Discord client and flag shutdown when it returns."""
+    try:
+        await client.start(token, log_handler=None)
+    finally:
+        shutdown_event.set()
+
+
+async def main() -> None:
+    if not TOKEN:
+        logger.error("Discord token missing - set DISCORD_TOKEN or configure netrc")
+        return
+
+    logger.info("Starting discord bot")
+    shutdown_event = asyncio.Event()
+    comm_stop_event = threading.Event()
+
+    comm_task = asyncio.create_task(_run_comm_subroutine(comm_stop_event))
+    bot_task = asyncio.create_task(_run_bot(TOKEN, shutdown_event))
+
+    try:
+        await shutdown_event.wait()
+    except (KeyboardInterrupt, asyncio.CancelledError):
+        logger.info("Shutdown signal received")
+        comm_stop_event.set()
+        await client.close()
+    finally:
+        comm_stop_event.set()
+        if not client.is_closed():
+            await client.close()
+        await asyncio.gather(bot_task, comm_task, return_exceptions=True)
+
+
 # *================================== Run
 if __name__ == "__main__":
-    logger.info("Starting discord bot")
-    threads = []
-    logger.info("Starting discord bot: Creating threads")
-    threads.append(threading.Thread(target=client.run, args=(TOKEN,),kwargs={"log_handler":None}))
-    threads.append(threading.Thread(target=comm_subroutine))
-    logger.info("Starting discord bot: Starting threads")
-    WRK_CNT = 0
-    for worker in threads:
-        WRK_CNT += 1
-        logger.info("Starting discord bot: Starting thread %s", WRK_CNT)
-        worker.start()
-    logger.info("Starting discord bot: Joining threads")
-    WRK_CNT = 0
-    for worker in threads:
-        WRK_CNT += 1
-        logger.info("Starting discord bot: Joining thread %s", WRK_CNT)
-        worker.join()
+    asyncio.run(main())