sx-http: Docker compose overlay + auto-detect component dir

docker-compose.dev-sx-native.yml overrides entrypoint to run OCaml
HTTP server inside Docker container (Caddy on externalnet can reach it).

Auto-detect sx component directory: checks /app/sx (Docker) first,
falls back to /project/sx/sx (dev). SX_COMPONENTS_DIR env override.

Live on sx.rose-ash.com via Caddy → Docker → OCaml HTTP server.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

docker-compose.dev-sx-native.yml

@@ -0,0 +1,14 @@
+# Native OCaml HTTP server for sx_docs — no Python, no Quart
+# Overrides dev-sx.yml entrypoint to use sx_server --http
+#
+# Usage:
+#   docker compose -p sx-dev -f docker-compose.dev-sx.yml -f docker-compose.dev-sx-native.yml up
+
+services:
+  sx_docs:
+    entrypoint: ["/app/bin/sx_server", "--http", "8000"]
+    environment:
+      SX_PROJECT_DIR: /app
+      SX_SPEC_DIR: /app/spec
+      SX_LIB_DIR: /app/lib
+      SX_WEB_DIR: /app/web

hosts/ocaml/bin/sx_server.ml

@@ -1695,8 +1695,14 @@ let http_mode port =
     project_dir ^ "/lib" in
   let web_base = try Sys.getenv "SX_WEB_DIR" with Not_found ->
     project_dir ^ "/web" in
-  let shared_sx = project_dir ^ "/shared/sx/templates" in
-  let sx_sx = project_dir ^ "/sx/sx" in
+  let shared_sx = try Sys.getenv "SX_SHARED_DIR" with Not_found ->
+    project_dir ^ "/shared/sx/templates" in
+  let sx_sx = try Sys.getenv "SX_COMPONENTS_DIR" with Not_found ->
+    (* Docker: /app/sx, dev: /project/sx/sx *)
+    let docker_path = project_dir ^ "/sx" in
+    let dev_path = project_dir ^ "/sx/sx" in
+    if Sys.file_exists (docker_path ^ "/page-functions.sx") then docker_path
+    else dev_path in
   let t0 = Unix.gettimeofday () in
   (* Core spec + adapters.
      Skip: primitives.sx (declarative metadata — all prims native in OCaml),