Fix Railpack/Railway start detection

Add root app.py and Procfile for uvicorn start; default bind to 0.0.0.0 and use platform PORT when provided.

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: nedpearson

Procfile

@@ -0,0 +1,2 @@
+web: uvicorn local_nexus_controller.main:app --host 0.0.0.0 --port $PORT
+

app.py

@@ -0,0 +1,9 @@
+"""
+Railpack/Railway-friendly entrypoint.
+
+Railpack will auto-start FastAPI apps if it can find an `app` object in
+`app.py` or `main.py` at the repository root. This file provides that.
+"""
+
+from local_nexus_controller.main import app  # noqa: F401
+

local_nexus_controller/settings.py

@@ -35,8 +35,14 @@ def load_settings() -> Settings:
     db_path_raw = os.getenv("LOCAL_NEXUS_DB_PATH", "data/local_nexus.db")
     db_path = (project_root / db_path_raw).resolve() if not Path(db_path_raw).is_absolute() else Path(db_path_raw)
 
-    host = os.getenv("LOCAL_NEXUS_HOST", "127.0.0.1")
-    port = _to_int(os.getenv("LOCAL_NEXUS_PORT"), 5010)
+    # Deployment-friendly defaults:
+    # - Platforms like Railway provide PORT; services must bind 0.0.0.0:$PORT.
+    platform_port = os.getenv("PORT")
+    host_default = "0.0.0.0" if platform_port else "127.0.0.1"
+    host = os.getenv("LOCAL_NEXUS_HOST", host_default)
+
+    port_raw = os.getenv("LOCAL_NEXUS_PORT") or platform_port
+    port = _to_int(port_raw, 5010)
     token = os.getenv("LOCAL_NEXUS_TOKEN") or None
 
     port_range_start = _to_int(os.getenv("LOCAL_NEXUS_PORT_RANGE_START"), 3000)