feat: public auto_approve probe + bump to v1.3.0-aio.5

Add GET /events/api/v1/events/settings/public — invoice-key-gated
(anyone with a wallet) — returning just `{ auto_approve }`. The webapp
needs this to render accurate edit-flow copy without forcing every
event creator to also be an LNbits admin.

The admin-only GET /settings stays the source of truth for the full
EventsSettings payload.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

config.json

@@ -1,6 +1,6 @@
 {
   "id": "events",
-  "version": "1.3.0-aio.4",
+  "version": "1.3.0-aio.5",
   "name": "Events",
   "repo": "https://git.atitlan.io/aiolabs/events",
   "short_description": "Sell and register event tickets",