chore(release): v1.6.8-aio.1

Rebase onto upstream v1.6.8, so the upstream segment moves and the aio
patch counter resets to 1.

- #63 merge upstream v1.6.8: ticket waves (per-wave price/currency/
  stock/fiat), paginated tickets, the organiser ticket-image template.
  Pricing and inventory now follow the wave the buyer selected rather
  than the primary-wave roll-up; npub checkout and DM delivery kept
  where upstream removed them; `_parse_date` accepts the ISO datetimes
  our closing dates carry.
- #63 drop the SatsPay/watchonly on-chain surface — on-chain will go
  through native LndRest once aiolabs/lnbits#53 lands (#41).
- #63 publish the active wave over Nostr, with `nostr_published_wave_id`
  (fork migration m004) so the reconciliation sweep republishes at wave
  boundaries (#61).
- #64 require a capacity on every ticket wave (#34, #62).

`migrations.py` stays byte-identical to upstream. v1.6.8 adds no
upstream migrations over v1.6.1 — waves live in `extra` JSON — so no
`dbversions` surgery is needed on existing installs; only the fork
namespace advances, `events_fork` 3 -> 4.

config.json

@@ -1,6 +1,6 @@
 {
   "id": "events",
-  "version": "1.6.1-aio.18",
+  "version": "1.6.8-aio.1",
   "name": "Events",
   "repo": "https://git.atitlan.io/aiolabs/events",
   "short_description": "Sell and register event tickets",