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>

deploy.sh

@@ -2,7 +2,7 @@
 set -euo pipefail
 
 REGISTRY="registry.rose-ash.com:5000"
-APPS="blog market cart events federation account relations likes orders test"
+APPS="blog market cart events federation account relations likes orders test sx_docs"
 
 usage() {
   echo "Usage: deploy.sh [app ...]"
@@ -15,6 +15,14 @@ usage() {
 
 cd "$(dirname "$0")"
 
+_app_dir() {
+  # Map compose service name to source directory when they differ
+  case "$1" in
+    sx_docs) echo "sx" ;;
+    *) echo "$1" ;;
+  esac
+}
+
 # Determine which apps to build
 if [ $# -eq 0 ]; then
   # Auto-detect: uncommitted changes + last commit
@@ -24,7 +32,8 @@ if [ $# -eq 0 ]; then
     BUILD=($APPS)
   else
     for app in $APPS; do
-      if echo "$CHANGED" | grep -q "^$app/"; then
+      dir=$(_app_dir "$app")
+      if echo "$CHANGED" | grep -q "^$dir/"; then
         BUILD+=("$app")
       fi
     done
@@ -56,8 +65,9 @@ echo "Unit tests passed."
 echo ""
 
 for app in "${BUILD[@]}"; do
+  dir=$(_app_dir "$app")
   echo "=== $app ==="
-  docker build -f "$app/Dockerfile" -t "$REGISTRY/$app:latest" .
+  docker build -f "$dir/Dockerfile" -t "$REGISTRY/$app:latest" .
   docker push "$REGISTRY/$app:latest"
   docker service update --force "coop_$app" 2>/dev/null \
     || echo "  (service coop_$app not running — will start on next stack deploy)"