feat: strengthen module contracts and shared WebUI runtime

tests/test_view_surfaces.py

@@ -5,6 +5,7 @@ import unittest
 from fastapi import FastAPI
 from fastapi.testclient import TestClient
 
+from govoplan_core.auth import get_api_principal
 from govoplan_core.core.modules import (
     FrontendModule,
     FrontendRoute,
@@ -218,6 +219,7 @@ class ViewSurfaceContractTests(unittest.TestCase):
         app = FastAPI()
         app.state.govoplan_registry = registry
         app.include_router(create_platform_router(), prefix="/api/v1")
+        app.dependency_overrides[get_api_principal] = lambda: object()
 
         with TestClient(app) as client:
             response = client.get("/api/v1/platform/modules")