feat: add GET /state handler to return determined state

Co-authored-by: aider (gemini/gemini-2.5-pro-preview-05-06) <aider@aider.chat>

server.py

@@ -121,6 +121,16 @@ async def handle_root(request):
     """Handler for the root GET request."""
     return web.Response(text="hello world")
 
+async def handle_state(request):
+    """Handler for the /state GET request."""
+    state = "unknown"
+    if len(PREDICTION_HISTORY) == PREDICTION_HISTORY_MAX_LENGTH:
+        if all(s == "open" for s in PREDICTION_HISTORY):
+            state = "open"
+        elif all(s == "closed" for s in PREDICTION_HISTORY):
+            state = "closed"
+    return web.Response(text=state)
+
 async def on_startup(app):
     """Actions to perform on application startup."""
     # Set up device
@@ -155,6 +165,7 @@ async def on_cleanup(app):
 def main():
     app = web.Application()
     app.router.add_get('/', handle_root)
+    app.router.add_get('/state', handle_state)
     app.on_startup.append(on_startup)
     app.on_cleanup.append(on_cleanup)
     web.run_app(app, port=8081)