Delete orders + federation sx_components.py — rendering inlined to routes

Phase 2 (Orders):
- Checkout error/return renders moved directly into route handlers
- Removed orphaned test_sx_helpers.py

Phase 3 (Federation):
- Auth pages use _render_social_auth_page() helper in routes
- Choose-username render inlined into identity routes
- Timeline/search/follow/interaction renders inlined into social routes
  using serializers imported from sxc.pages
- Added _social_page() to sxc/pages/__init__.py for shared use
- Home page renders inline in app.py

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

orders/app.py

@@ -1,7 +1,5 @@
 from __future__ import annotations
 import path_setup  # noqa: F401  # adds shared/ to sys.path
-import sx.sx_components as sx_components  # noqa: F401  # ensure Hypercorn --reload watches this file
-
 from pathlib import Path
 from types import SimpleNamespace
 
@@ -69,10 +67,9 @@ def create_app() -> "Quart":
         app.jinja_loader,
     ])
 
-    # Load orders-specific s-expression components (loaded at import time)
-    import sx.sx_components  # noqa: F811
-
-    # Setup defpage routes
+    # Load .sx component files and setup defpage routes
+    from shared.sx.jinja_bridge import load_service_components
+    load_service_components(str(Path(__file__).resolve().parent), service_name="orders")
     from sxc.pages import setup_orders_pages
     setup_orders_pages()