Add standalone mode for sx-web.org deployment

- SX_STANDALONE=true env var: no OAuth, no root header, no cross-service
  fragments. Same image runs in both rose-ash cooperative and standalone.
- Factory: added no_oauth parameter to create_base_app()
- Standalone layout defcomps skip ~root-header-auto/~root-mobile-auto
- Fixed Dockerfile: was missing sx/sx/ component directory copy
- CI: deploys sx-web swarm stack on main branch when sx changes
- Stack config at ~/sx-web/ (Caddy → sx_docs, Redis)

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

sx/app.py

@@ -1,10 +1,12 @@
 from __future__ import annotations
+import os
 import path_setup  # noqa: F401
-from shared.infrastructure.factory import create_base_app
 
 from bp import register_pages
 from services import register_domain_services
 
+SX_STANDALONE = os.getenv("SX_STANDALONE") == "true"
+
 
 async def sx_docs_context() -> dict:
     """SX docs app context processor — fetches cross-service fragments."""
@@ -39,11 +41,29 @@ async def sx_docs_context() -> dict:
     return ctx
 
 
+async def sx_standalone_context() -> dict:
+    """Minimal context for standalone mode — no cross-service fragments."""
+    from shared.infrastructure.context import base_context
+    ctx = await base_context()
+    ctx["menu_items"] = []
+    ctx["cart_mini"] = ""
+    ctx["auth_menu"] = ""
+    ctx["nav_tree"] = ""
+    return ctx
+
+
 def create_app() -> "Quart":
+    from shared.infrastructure.factory import create_base_app
+
+    extra_kw = {}
+    if SX_STANDALONE:
+        extra_kw["no_oauth"] = True
+
     app = create_base_app(
         "sx",
-        context_fn=sx_docs_context,
+        context_fn=sx_standalone_context if SX_STANDALONE else sx_docs_context,
         domain_services_fn=register_domain_services,
+        **extra_kw,
     )
 
     from sxc.pages import setup_sx_pages