Land prototype on main (fix stacked-PR retarget gap)

PRs #10 and #11 were merged into their intermediate base branches
(restructure/working-copy-root and proto-improvements) rather than main,
because the stacked PRs' bases were not auto-retargeted (the branches were
not deleted on merge). As a result main only received the #9 restructure
and is still the plain working-copy bot.

This brings the full prototype onto main as a clean delta on top of the
current main tree (identical content to proto-improvements, but with main
ancestry so it merges without the squash-induced rename/delete conflicts):

- constants.py: env-var config, safe JSON loading, dependency guards,
  env->netrc tokens, API_SHARED_KEY + service_headers(), CONAN_* config
- communication_subroutine.py: queue timeout/Empty, daemon threads,
  cooperative stop_event, inbound _authorize_request()
- bot.py: asyncio event loop + load conanjurer_commands
- music_functions / radio_commands / librarian_commands: X-Conjurer-Api-Key
- conanjurer_commands/_functions: fixed + integrated bridge with RCON
  player-join notifications
- requirements_bot.txt: aiomcrcon, asyncssh
- conjurer_musician/.gitignore: keep runtime playlists/mp3 out of the repo

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

radio_commands.py

@@ -8,7 +8,9 @@ import uuid
 
 import asyncio
 from datetime import datetime
-from constants import RADIO_HARBOR_ADDRESS, SKIP_TRACK, FILE_SERVICE_ADDRESS, ADD_TO_PRIO_PLAYLIST, REQUEST_MUSIC, CREATE_PRIO_PLAYLIST, CLEAR_PRIO
+from constants import RADIO_HARBOR_ADDRESS, SKIP_TRACK, FILE_SERVICE_ADDRESS, ADD_TO_PRIO_PLAYLIST, REQUEST_MUSIC, CREATE_PRIO_PLAYLIST, CLEAR_PRIO, service_headers
+
+SERVICE_HEADERS = service_headers()
 
 class RadioModule(commands.Cog):
     def __init__(self, bot, logger_name):
@@ -34,6 +36,7 @@ class RadioModule(commands.Cog):
                 coroutine = asyncio.to_thread(
                     requests.get,
                     f"{RADIO_HARBOR_ADDRESS}{SKIP_TRACK}",
+                    headers=SERVICE_HEADERS,
                     timeout=360,
                 )
                 result = await coroutine
@@ -95,6 +98,7 @@ class RadioModule(commands.Cog):
                 requests.post,
                 f"{FILE_SERVICE_ADDRESS}{ADD_TO_PRIO_PLAYLIST}",
                 json=jrequest,
+                headers=SERVICE_HEADERS,
                 timeout=360,
             )
             result = await coroutine
@@ -130,6 +134,7 @@ class RadioModule(commands.Cog):
                 requests.post,
                 f"{FILE_SERVICE_ADDRESS}{REQUEST_MUSIC}",
                 json=jrequest,
+                headers=SERVICE_HEADERS,
                 timeout=360,
             )
             result = await coroutine
@@ -167,6 +172,7 @@ class RadioModule(commands.Cog):
                 requests.post,
                 f"{FILE_SERVICE_ADDRESS}{CREATE_PRIO_PLAYLIST}",
                 json=jrequest,
+                headers=SERVICE_HEADERS,
                 timeout=360,
             )
             result = await coroutine
@@ -194,6 +200,7 @@ class RadioModule(commands.Cog):
             coroutine = asyncio.to_thread(
                 requests.get,
                 f"{FILE_SERVICE_ADDRESS}{CLEAR_PRIO}",
+                headers=SERVICE_HEADERS,
                 timeout=360,
             )
             result = await coroutine