chore(release): v1.6.1-aio.16

Nostr publish reliability.

- #54 the two paths that skip a NIP-52 publish now log at WARNING
  instead of silently (bare return / debug); publish failures moved to
  ERROR
- #55 `events.nostr_publish_pending` marks a row from before each
  publish attempt until a confirmed success, and a 5-minute sweep
  republishes whatever is still flagged, so drift recovers on its own
  instead of waiting for an operator who knows to run /republish-all
- #55 the NostrClient send loop holds and retries a dequeued req
  (bounded at 3) rather than dropping it

Adds migration m003 (events.nostr_publish_pending). Verified on bohm:
events_fork 1 -> 3, column present, event created and published to a
relay with the flag clearing on success.

config.json

@@ -1,6 +1,6 @@
 {
   "id": "events",
-  "version": "1.6.1-aio.15",
+  "version": "1.6.1-aio.16",
   "name": "Events",
   "repo": "https://git.atitlan.io/aiolabs/events",
   "short_description": "Sell and register event tickets",