Re-enable Gradio web UI at / for friendly browser-facing Space page

Switches server/app.py from create_fastapi_app to create_app, which serves
the OpenEnv Gradio UI at / when ENABLE_WEB_INTERFACE=true (already set in
the Dockerfile). All the standard HTTP API routes (/reset, /step, /state,
etc.) still work the same way — only the root URL changes from 404 to the
project page.

server/app.py

@@ -1,25 +1,31 @@
 """FastAPI application for DispatchPulse.
 
-Uses ``create_fastapi_app(env_factory, ActionCls, ObservationCls)`` from
-openenv-core's HTTP server, which exposes the standard ``/reset``, ``/step``,
-``/state``, ``/health``, ``/metadata``, ``/schema``, and ``/ws`` routes.
+Uses ``create_app(env_factory, ActionCls, ObservationCls)`` from
+openenv-core's HTTP server. This wrapper:
+
+- When ``ENABLE_WEB_INTERFACE=true`` (set in the Dockerfile): serves the
+  OpenEnv Gradio web UI at ``/`` so judges visiting the Space in a browser
+  see a friendly project page.
+- Always registers the standard ``/reset``, ``/step``, ``/state``,
+  ``/health``, ``/metadata``, ``/schema``, and ``/ws`` routes — these are
+  what the hackathon grader actually hits.
 """
 
 from __future__ import annotations
 
+import os
+import sys
+
 # Support both in-repo and standalone imports.
 try:
-    from openenv.core.env_server.http_server import create_fastapi_app
+    from openenv.core.env_server.http_server import create_app
 
     from .environment import DispatchPulseEnvironment
 except ImportError:  # pragma: no cover
-    from openenv.core.env_server.http_server import create_fastapi_app
+    from openenv.core.env_server.http_server import create_app
     from server.environment import DispatchPulseEnvironment
 
 # Import the typed Action / Observation classes from the project root models.py
-import os
-import sys
-
 _PKG_ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
 if _PKG_ROOT not in sys.path:
     sys.path.insert(0, _PKG_ROOT)
@@ -27,10 +33,12 @@ if _PKG_ROOT not in sys.path:
 from models import DispatchPulseAction, DispatchPulseObservation  # noqa: E402
 
 # Pass the class (factory) so each session gets its own env instance.
-app = create_fastapi_app(
+# ``env_name`` controls the web UI title and README lookup.
+app = create_app(
     DispatchPulseEnvironment,
     DispatchPulseAction,
     DispatchPulseObservation,
+    env_name="dispatchpulse",
     max_concurrent_envs=8,
 )