Rebrand sexp → sx across web platform (173 files)

Rename all sexp directories, files, identifiers, and references to sx.
artdag/ excluded (separate media processing DSL).

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

docker-compose.dev.yml

@@ -45,7 +45,7 @@ services:
       - ./blog/alembic.ini:/app/blog/alembic.ini:ro
       - ./blog/alembic:/app/blog/alembic:ro
       - ./blog/app.py:/app/app.py
-      - ./blog/sexp:/app/sexp
+      - ./blog/sx:/app/sx
       - ./blog/bp:/app/bp
       - ./blog/services:/app/services
       - ./blog/templates:/app/templates
@@ -83,7 +83,7 @@ services:
       - ./market/alembic.ini:/app/market/alembic.ini:ro
       - ./market/alembic:/app/market/alembic:ro
       - ./market/app.py:/app/app.py
-      - ./market/sexp:/app/sexp
+      - ./market/sx:/app/sx
       - ./market/bp:/app/bp
       - ./market/services:/app/services
       - ./market/templates:/app/templates
@@ -120,7 +120,7 @@ services:
       - ./cart/alembic.ini:/app/cart/alembic.ini:ro
       - ./cart/alembic:/app/cart/alembic:ro
       - ./cart/app.py:/app/app.py
-      - ./cart/sexp:/app/sexp
+      - ./cart/sx:/app/sx
       - ./cart/bp:/app/bp
       - ./cart/services:/app/services
       - ./cart/templates:/app/templates
@@ -157,7 +157,7 @@ services:
       - ./events/alembic.ini:/app/events/alembic.ini:ro
       - ./events/alembic:/app/events/alembic:ro
       - ./events/app.py:/app/app.py
-      - ./events/sexp:/app/sexp
+      - ./events/sx:/app/sx
       - ./events/bp:/app/bp
       - ./events/services:/app/services
       - ./events/templates:/app/templates
@@ -194,7 +194,7 @@ services:
       - ./federation/alembic.ini:/app/federation/alembic.ini:ro
       - ./federation/alembic:/app/federation/alembic:ro
       - ./federation/app.py:/app/app.py
-      - ./federation/sexp:/app/sexp
+      - ./federation/sx:/app/sx
       - ./federation/bp:/app/bp
       - ./federation/services:/app/services
       - ./federation/templates:/app/templates
@@ -231,7 +231,7 @@ services:
       - ./account/alembic.ini:/app/account/alembic.ini:ro
       - ./account/alembic:/app/account/alembic:ro
       - ./account/app.py:/app/app.py
-      - ./account/sexp:/app/sexp
+      - ./account/sx:/app/sx
       - ./account/bp:/app/bp
       - ./account/services:/app/services
       - ./account/templates:/app/templates
@@ -330,7 +330,7 @@ services:
       - ./orders/alembic.ini:/app/orders/alembic.ini:ro
       - ./orders/alembic:/app/orders/alembic:ro
       - ./orders/app.py:/app/app.py
-      - ./orders/sexp:/app/sexp
+      - ./orders/sx:/app/sx
       - ./orders/bp:/app/bp
       - ./orders/services:/app/services
       - ./orders/templates:/app/templates
@@ -361,7 +361,7 @@ services:
       - /root/rose-ash/_config/app-config.yaml:/app/config/app-config.yaml:ro
       - ./shared:/app/shared
       - ./test/app.py:/app/app.py
-      - ./test/sexp:/app/sexp
+      - ./test/sx:/app/sx
       - ./test/bp:/app/bp
       - ./test/services:/app/services
       - ./test/runner.py:/app/runner.py