Add vue-router, login/setup flow and backend logging

Refactor frontend to route-based navigation with vue-router, add
system setup and login pages with API integration. Add structured
logging, access-log middleware and startup lifecycle to FastAPI
backend.

.env.example

@@ -0,0 +1,44 @@
+APP_NAME=X-Financial
+APP_ENV=local
+APP_DEBUG=true
+API_V1_PREFIX=/api/v1
+SETUP_COMPLETED=false
+VITE_SETUP_COMPLETED=false
+
+COMPANY_NAME=
+COMPANY_CODE=
+ADMIN_EMAIL=
+VITE_COMPANY_NAME=
+VITE_COMPANY_CODE=
+VITE_ADMIN_EMAIL=
+# Admin login credentials are stored separately under server/.secrets/
+
+WEB_HOST=127.0.0.1
+WEB_PORT=5173
+VITE_WEB_HOST=127.0.0.1
+VITE_WEB_PORT=5173
+
+SERVER_HOST=127.0.0.1
+SERVER_PORT=8000
+VITE_SERVER_HOST=127.0.0.1
+VITE_SERVER_PORT=8000
+SERVER_STARTUP_TIMEOUT=300
+VITE_API_BASE_URL=http://127.0.0.1:8000/api/v1
+
+POSTGRES_HOST=127.0.0.1
+POSTGRES_PORT=5432
+POSTGRES_DB=x_financial
+POSTGRES_USER=postgres
+POSTGRES_PASSWORD=postgres
+VITE_POSTGRES_HOST=127.0.0.1
+VITE_POSTGRES_PORT=5432
+VITE_POSTGRES_DB=x_financial
+VITE_POSTGRES_USER=postgres
+
+DATABASE_URL=postgresql+psycopg://postgres:postgres@127.0.0.1:5432/x_financial
+SQLALCHEMY_ECHO=false
+
+REDIS_URL=
+VITE_REDIS_URL=
+
+CORS_ORIGINS='["http://127.0.0.1:5173","http://localhost:5173"]'