US08-01: Make the Trust Boundary Configurable and Authenticated

photo_pipeline/__main__.py

@@ -209,15 +209,25 @@ def main(argv: Sequence[str] | None = None) -> int:
             lock.release()
         return 0
 
+    import sys
+
     import uvicorn
 
-    from photo_pipeline.api.app import create_app
+    from photo_pipeline.api.app import ConfigurationRefused, create_app
+
+    # An exposed deployment without an access secret must not reach the port at all,
+    # and the operator needs a sentence, not a traceback (US08-01).
+    try:
+        app = create_app(config)
+    except ConfigurationRefused as error:
+        print(str(error), file=sys.stderr)
+        return 4
 
     lock = LibraryLock(config, "api")
     if (held := _acquire(lock, allow_legacy=args.allow_legacy)) is not None:
         return held
     try:
-        uvicorn.run(create_app(config), host=config.host, port=config.port)
+        uvicorn.run(app, host=config.host, port=config.port)
     finally:
         lock.release()
     return 0