Bind OP25 control API and terminal to loopback by default

Both :8001 (FastAPI control API) and :8081 (OP25's HTTP terminal) listened on
0.0.0.0 with no authentication, on a container that is privileged with /dev
mounted and network_mode: host. Nodes get deployed to third-party sites, so
that exposed start/stop/retune to anyone on the host's LAN.

All three containers share the host network namespace, so edge-node still
reaches both over 127.0.0.1 unchanged. OP25_DEBUG_EXPOSE=true restores the
old 0.0.0.0 binding and logs a loud warning; it is off by default.

Confirmed against boatbod/op25 gr310 that the terminal's http:<host>:<port>
string is honoured as a real bind address (http_server.py splits it and hands
the host to create_server), so no flag was invented.

Also reorder models.py so IcecastConfig precedes ConfigGenerator, which
annotates a field with it. That only worked because python:slim-trixie is
currently Python 3.14, where PEP 649 defers annotation evaluation; on 3.13 or
earlier the same file is a hard NameError at import.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

op25-container/app/main.py

@@ -5,12 +5,20 @@ import routers.op25_controller as op25_controller
 from internal.logger import create_logger
 from internal.liquidsoap_config_utils import generate_liquid_script
 from models import IcecastConfig
+from config import settings, bind_host
 
 LOGGER = create_logger(__name__)
 
 
 @asynccontextmanager
 async def lifespan(app: FastAPI):
+    if settings.op25_debug_expose:
+        LOGGER.warning(
+            "OP25_DEBUG_EXPOSE=true — the op25 control API (:8001) and OP25's "
+            "HTTP terminal (:8081) are bound to 0.0.0.0 and reachable by "
+            "ANYTHING on this node's LAN with NO authentication. This is a "
+            "debugging aid only; do not leave it set on a deployed node."
+        )
     try:
         config = IcecastConfig(
             icecast_host=os.getenv("ICECAST_HOST", "localhost"),
@@ -28,3 +36,12 @@ async def lifespan(app: FastAPI):
 app = FastAPI(lifespan=lifespan)
 
 app.include_router(op25_controller.create_op25_router(), prefix="/op25")
+
+
+if __name__ == "__main__":
+    # Launched directly (see Dockerfile CMD) instead of via `uvicorn main:app
+    # --host ...` so the bind address is driven by OP25_DEBUG_EXPOSE (config.py)
+    # rather than a value baked into the image at build time.
+    import uvicorn
+
+    uvicorn.run("main:app", host=bind_host(), port=8001, reload=True)