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/Dockerfile

@@ -0,0 +1,58 @@
+# syntax=docker/dockerfile:1
+
+FROM python:3.11-slim AS base
+
+ENV PYTHONDONTWRITEBYTECODE=1 \
+    PYTHONUNBUFFERED=1 \
+    PYTHONPATH=/app \
+    PIP_NO_CACHE_DIR=1 \
+    APP_PORT=8000 \
+    APP_MODULE=app:app
+
+WORKDIR /app
+
+RUN apt-get update && apt-get install -y --no-install-recommends \
+      ca-certificates nodejs \
+    && rm -rf /var/lib/apt/lists/*
+
+COPY shared/requirements.txt ./requirements.txt
+RUN pip install -r requirements.txt
+
+# Shared code
+COPY shared/ ./shared/
+
+# App code
+COPY sx/ ./sx-app-tmp/
+RUN cp -r sx-app-tmp/app.py sx-app-tmp/path_setup.py \
+         sx-app-tmp/bp sx-app-tmp/sxc sx-app-tmp/services \
+         sx-app-tmp/content sx-app-tmp/__init__.py ./ 2>/dev/null || true && \
+    rm -rf sx-app-tmp
+
+# Sibling models for cross-domain SQLAlchemy imports
+COPY blog/__init__.py     ./blog/__init__.py
+COPY blog/models/         ./blog/models/
+COPY market/__init__.py   ./market/__init__.py
+COPY market/models/       ./market/models/
+COPY cart/__init__.py     ./cart/__init__.py
+COPY cart/models/         ./cart/models/
+COPY events/__init__.py   ./events/__init__.py
+COPY events/models/       ./events/models/
+COPY federation/__init__.py  ./federation/__init__.py
+COPY federation/models/      ./federation/models/
+COPY account/__init__.py  ./account/__init__.py
+COPY account/models/      ./account/models/
+COPY relations/__init__.py ./relations/__init__.py
+COPY relations/models/ ./relations/models/
+COPY likes/__init__.py ./likes/__init__.py
+COPY likes/models/ ./likes/models/
+COPY orders/__init__.py ./orders/__init__.py
+COPY orders/models/ ./orders/models/
+
+COPY sx/entrypoint.sh /usr/local/bin/entrypoint.sh
+RUN chmod +x /usr/local/bin/entrypoint.sh
+
+RUN useradd -m -u 10001 appuser && chown -R appuser:appuser /app
+USER appuser
+
+EXPOSE ${APP_PORT}
+ENTRYPOINT ["/usr/local/bin/entrypoint.sh"]