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>

events/bp/slot/routes.py

@@ -24,7 +24,7 @@ from shared.browser.app.utils import (
     parse_cost
 )
 from shared.browser.app.utils.htmx import is_htmx_request
-from shared.sexp.helpers import sexp_response
+from shared.sx.helpers import sx_response
 
 
 def register():
@@ -75,8 +75,8 @@ def register():
         slot = await svc_get_slot(g.s, slot_id)
         if not slot:
             return await make_response("Not found", 404)
-        from sexp.sexp_components import render_slot_main_panel
-        return sexp_response(render_slot_main_panel(slot, g.calendar))
+        from sx.sx_components import render_slot_main_panel
+        return sx_response(render_slot_main_panel(slot, g.calendar))
 
     @bp.delete("/")
     @require_admin
@@ -84,8 +84,8 @@ def register():
     async def slot_delete(slot_id: int, **kwargs):
         await svc_delete_slot(g.s, slot_id)
         slots = await svc_list_slots(g.s, g.calendar.id)
-        from sexp.sexp_components import render_slots_table
-        return sexp_response(render_slots_table(slots, g.calendar))
+        from sx.sx_components import render_slots_table
+        return sx_response(render_slots_table(slots, g.calendar))
 
     @bp.put("/")
     @require_admin
@@ -166,8 +166,8 @@ def register():
                 }
             ), 422
 
-        from sexp.sexp_components import render_slot_main_panel
-        return sexp_response(render_slot_main_panel(slot, g.calendar, oob=True))
+        from sx.sx_components import render_slot_main_panel
+        return sx_response(render_slot_main_panel(slot, g.calendar, oob=True))