Add sx documentation app (sx.rose-ash.com)

New public-facing service documenting the s-expression rendering engine.
Modelled on four.htmx.org with violet theme, all content rendered via sx.

Sections: docs, reference, protocols, examples (live demos), essays
(including "sx sucks"). No database — purely static documentation.

Port 8012, Redis DB 10. CI and deploy.sh updated with app_dir() mapping
for sx_docs -> sx/ directory. Caddy reverse proxy entry added separately.

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

sx/app.py

@@ -0,0 +1,45 @@
+from __future__ import annotations
+import path_setup  # noqa: F401
+import sxc.sx_components as sx_components  # noqa: F401
+
+from shared.infrastructure.factory import create_base_app
+from shared.sx.jinja_bridge import render
+
+from bp import register_pages
+from services import register_domain_services
+
+
+async def sx_docs_context() -> dict:
+    """SX docs app context processor — minimal, no cross-service fragments."""
+    from shared.infrastructure.context import base_context
+
+    ctx = await base_context()
+    ctx["menu_items"] = []
+    blog_url = ctx.get("blog_url", "")
+    if callable(blog_url):
+        blog_url_str = blog_url("")
+    else:
+        blog_url_str = str(blog_url or "")
+    ctx["cart_mini"] = render(
+        "cart-mini", cart_count=0, blog_url=blog_url_str, cart_url="",
+    )
+    ctx["auth_menu"] = ""
+    ctx["nav_tree"] = ""
+    return ctx
+
+
+def create_app() -> "Quart":
+    app = create_base_app(
+        "sx",
+        context_fn=sx_docs_context,
+        domain_services_fn=register_domain_services,
+    )
+
+    import sxc.sx_components  # noqa: F401
+
+    app.register_blueprint(register_pages(url_prefix="/"))
+
+    return app
+
+
+app = create_app()