Refine events + sx sub-module imports from background agents

Events: route imports now point to specific sub-modules (entries,
tickets, slots) instead of all going through renders.py. Merged
layouts into helpers.py. __init__.py now 20 lines.

SX Docs: moved dispatchers from helpers.py into essays.py, cleaned
up __init__.py to 24 lines.

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

events/sxc/pages/entries.py

@@ -210,7 +210,7 @@ async def _entry_main_panel_html(ctx: dict) -> str:
     """Render the entry detail panel (name, slot, time, state, cost, tickets,
     buy form, date, posts, options + edit button)."""
     from quart import url_for
-    from .tickets import render_buy_form, render_entry_tickets_config
+    from .tickets import render_buy_form
 
     entry = ctx.get("entry")
     if not entry: