feat: initialize events app with calendars, slots, tickets, and internal API

Extract events/calendar functionality into standalone microservice:
- app.py and events_api.py from apps/events/
- Calendar blueprints (calendars, calendar, calendar_entries, calendar_entry, day, slots, slot, ticket_types, ticket_type)
- Templates for all calendar/event views including admin
- Dockerfile (APP_MODULE=app:app, IMAGE=events)
- entrypoint.sh (no Alembic - migrations managed by blog app)
- Gitea CI workflow for build and deploy

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

app.py

@@ -0,0 +1,54 @@
+from __future__ import annotations
+
+from quart import g
+
+from shared.factory import create_base_app
+
+from suma_browser.app.bp import register_calendars
+
+
+async def events_context() -> dict:
+    """
+    Events app context processor.
+
+    - menu_items: fetched from coop internal API
+    - cart_count/cart_total: fetched from cart internal API
+    """
+    from shared.context import base_context
+    from shared.internal_api import get as api_get, dictobj
+
+    ctx = await base_context()
+
+    # Menu items from coop API (wrapped for attribute access in templates)
+    menu_data = await api_get("coop", "/internal/menu-items")
+    ctx["menu_items"] = dictobj(menu_data) if menu_data else []
+
+    # Cart data from cart API
+    cart_data = await api_get("cart", "/internal/cart/summary", forward_session=True)
+    if cart_data:
+        ctx["cart_count"] = cart_data.get("count", 0)
+        ctx["cart_total"] = cart_data.get("total", 0)
+    else:
+        ctx["cart_count"] = 0
+        ctx["cart_total"] = 0
+
+    return ctx
+
+
+def create_app() -> "Quart":
+    app = create_base_app("events", context_fn=events_context)
+
+    # Calendars blueprint at root — standalone mode (no post nesting)
+    app.register_blueprint(
+        register_calendars(),
+        url_prefix="/calendars",
+    )
+
+    # Internal API (server-to-server, CSRF-exempt)
+    from .events_api import register as register_events_api
+    app.register_blueprint(register_events_api())
+
+    return app
+
+
+app = create_app()