refactor: drop the SatsPay/watchonly on-chain surface

v1.6.8 sells tickets on-chain through SatsPay charges — a per-purchase
watchonly address, a hosted charge page, and a webhook back into the
extension. We are not adopting that: on-chain goes through the fork's
native LndRestWallet support once core can mint purpose-bound receiving
addresses (aiolabs/lnbits#53). This is the parity note on #41, applied
as its own commit so the merge it follows stays a faithful diff of what
upstream shipped.

Removed:
- services: the five SatsPay/watchonly HTTP clients (and with them the
  only uses of httpx and typing.Any in that module)
- views_api: _get_watchonly_status, GET /events/onchain/status, the
  SatsPay charge branch of api_ticket_create, POST
  /tickets/{id}/satspay-webhook, PUT /tickets/{hash}/onchain-confirm
- models: EventExtra.onchain_{enabled,wallet_id,zeroconf,fasttrack},
  TicketExtra.satspay_charge_id, TicketPaymentRequest.satspay_charge_url
- frontend: the organiser's "Onchain payments" panel and its watchonly
  wallet picker, the per-ticket confirm-onchain button, the SatsPay
  charge-page redirect, and the wallet-status fetch behind them

`onchain` is no longer an accepted payment_method — there is no rail to
fulfil it until #41 lands, so accepting it could only fail later.

Kept as vocabulary for #41, in upstream's field names so it needs no
migration: TicketExtra.onchain / onchain_address and
TicketPaymentRequest.onchain_amount_sat.

35 routes register with no duplicates; ruff, black, prettier clean; 97
tests pass; mypy error set still identical to HEAD's baseline.

views_api.py

@@ -38,7 +38,6 @@ from lnbits.utils.exchange_rates import (
     satoshis_amount_as_fiat,
 )
 from lnbits.utils.nostr import normalize_public_key
-from loguru import logger
 from PIL import Image
 
 from .crud import (
@@ -99,11 +98,7 @@ from .qr import (
     ticket_card_filename,
 )
 from .services import (
-    create_satspay_charge,
     event_promo_usage,
-    fetch_watchonly_config,
-    fetch_watchonly_wallets,
-    get_satspay_charge,
     hydrate_promo_usage,
     refund_tickets,
     resend_ticket_email_notification,
@@ -112,7 +107,6 @@ from .services import (
 )
 from .tasks import (
     deregister_payment_listener,
-    payment_listeners,
     register_payment_listener,
 )
 
@@ -123,35 +117,6 @@ promo_api_router = APIRouter(prefix="/api/v1/promo")
 tickets_filters = parse_filters(TicketFilters)
 
 
-async def _get_watchonly_status(wallet) -> dict[str, Any]:
-    try:
-        config = await fetch_watchonly_config(wallet.inkey)
-        network = config.get("network")
-        if not network:
-            raise HTTPException(
-                status_code=HTTPStatus.BAD_REQUEST,
-                detail="Watchonly extension returned an invalid network.",
-            )
-        wallets = await fetch_watchonly_wallets(wallet.inkey, network)
-    except HTTPException:
-        raise
-    except Exception as exc:
-        return {
-            "available": False,
-            "message": f"Watchonly extension is not reachable: {exc!s}",
-            "network": None,
-            "wallets": [],
-            "mempool_endpoint": None,
-        }
-    return {
-        "available": True,
-        "message": None,
-        "network": network,
-        "wallets": wallets,
-        "mempool_endpoint": config.get("mempool_endpoint"),
-    }
-
-
 def _is_fiat_currency(currency: str | None) -> bool:
     return str(currency or "").lower() not in {"sat", "sats"}
 
@@ -294,13 +259,6 @@ async def api_get_settings_public(
     return {"auto_approve": settings.auto_approve}
 
 
-@events_api_router.get("/onchain/status")
-async def api_onchain_status(
-    wallet: WalletTypeInfo = Depends(require_admin_key),
-) -> dict[str, Any]:
-    return await _get_watchonly_status(wallet.wallet)
-
-
 @events_api_router.get("/{event_id}", response_model=PublicEvent)
 async def api_get_event(event_id: str) -> Event:
     """Public event detail used by display.vue.
@@ -821,7 +779,7 @@ async def api_ticket_create(
     refund_address = data.refund_address
     nostr_identifier = data.nostr_identifier.strip() if data.nostr_identifier else None
     payment_method = (data.payment_method or "lightning").lower()
-    if payment_method not in {"lightning", "fiat", "onchain"}:
+    if payment_method not in {"lightning", "fiat"}:
         raise HTTPException(
             status_code=HTTPStatus.BAD_REQUEST,
             detail="Unsupported payment method.",
@@ -931,7 +889,6 @@ async def api_ticket_create(
     invoice_unit = selected_wave.currency
     fiat_amount = price
     fiat_provider = None
-    onchain_amount_sat = None
 
     if payment_method == "fiat":
         if _is_fiat_currency(selected_wave.currency):
@@ -956,80 +913,6 @@ async def api_ticket_create(
                 status_code=HTTPStatus.BAD_REQUEST,
                 detail="No fiat payment provider configured for this event.",
             )
-    elif payment_method == "onchain":
-        onchain_amount_sat = int(price)
-        wallet_record = await get_wallet(event.wallet)
-        if not wallet_record:
-            raise HTTPException(
-                status_code=HTTPStatus.NOT_FOUND,
-                detail="Event wallet does not exist.",
-            )
-        if not event.extra.onchain_enabled:
-            raise HTTPException(
-                status_code=HTTPStatus.BAD_REQUEST,
-                detail="Onchain payments are not enabled for this event.",
-            )
-        if not event.extra.onchain_wallet_id:
-            raise HTTPException(
-                status_code=HTTPStatus.BAD_REQUEST,
-                detail="No onchain wallet configured for this event.",
-            )
-
-        ticket_id = urlsafe_short_hash()
-        base_url = str(request.base_url).rstrip("/")
-        # Use internal address for webhook — SatsPay calls it server-side and
-        # cannot reach the public domain from within the container.
-        internal_base = f"http://{settings.host}:{settings.port}"
-        webhook_url = (
-            f"{internal_base}/events/api/v1/tickets/{ticket_id}/satspay-webhook"
-        )
-        complete_url = f"{base_url}/events/ticket/{ticket_id}"
-        try:
-            charge = await create_satspay_charge(
-                api_key=wallet_record.inkey,
-                data={
-                    "amount": onchain_amount_sat,
-                    "description": f"Ticket for {event.name}",
-                    "name": name,
-                    "onchainwallet": event.extra.onchain_wallet_id,
-                    "zeroconf": event.extra.onchain_zeroconf,
-                    "fasttrack": event.extra.onchain_fasttrack,
-                    "webhook": webhook_url,
-                    "completelink": complete_url,
-                    "completelinktext": "View your ticket",
-                    "time": 1440,
-                },
-            )
-        except Exception as exc:
-            raise HTTPException(
-                status_code=HTTPStatus.BAD_REQUEST,
-                detail=f"Failed to create SatsPay charge: {exc}",
-            ) from exc
-
-        await create_ticket(
-            payment_hash=ticket_id,
-            wallet=event.wallet,
-            event=event.id,
-            name=name,
-            email=email,
-            extra={
-                "applied_promo_code": promo_code,
-                "ticket_wave_id": selected_wave.id,
-                "ticket_wave_title": selected_wave.title,
-                "refund_address": refund_address,
-                "nostr_identifier": nostr_identifier,
-                "ticket_base_url": base_url,
-                "sats_paid": onchain_amount_sat,
-                "onchain": True,
-                "satspay_charge_id": charge["id"],
-            },
-        )
-
-        return TicketPaymentRequest(
-            payment_hash=ticket_id,
-            onchain_amount_sat=onchain_amount_sat,
-            satspay_charge_url=f"/satspay/{charge['id']}",
-        )
     else:
         invoice_unit = "sat"
 
@@ -1194,73 +1077,6 @@ async def api_ticket_delete(
     await delete_ticket(ticket_id)
 
 
-@tickets_api_router.post("/{ticket_id}/satspay-webhook")
-async def api_ticket_satspay_webhook(ticket_id: str) -> None:
-    ticket = await get_ticket(ticket_id)
-    if not ticket:
-        logger.warning(f"SatsPay webhook: ticket {ticket_id} does not exist.")
-        raise HTTPException(
-            status_code=HTTPStatus.NOT_FOUND, detail="Ticket does not exist."
-        )
-    if ticket.paid:
-        logger.warning(f"SatsPay webhook: ticket {ticket_id} already paid.")
-        return
-    if not ticket.extra.satspay_charge_id:
-        raise HTTPException(
-            status_code=HTTPStatus.BAD_REQUEST, detail="Not a SatsPay ticket."
-        )
-    wallet = await get_wallet(ticket.wallet)
-    if not wallet:
-        raise HTTPException(
-            status_code=HTTPStatus.NOT_FOUND, detail="Ticket wallet does not exist."
-        )
-    try:
-        charge = await get_satspay_charge(wallet.inkey, ticket.extra.satspay_charge_id)
-    except Exception as exc:
-        raise HTTPException(
-            status_code=HTTPStatus.BAD_REQUEST, detail=f"Could not verify charge: {exc}"
-        ) from exc
-    if not charge.get("paid"):
-        logger.warning(
-            f"SatsPay webhook for ticket {ticket_id}: charge"
-            f" {ticket.extra.satspay_charge_id} not paid."
-        )
-        return
-
-    ticket = await set_ticket_paid(ticket)
-    send_ticket_notification_in_background(ticket)
-    for queue in payment_listeners.get(ticket_id, []):
-        queue.put_nowait(ticket)
-
-
-@tickets_api_router.put("/{payment_hash}/onchain-confirm")
-async def api_ticket_onchain_confirm(
-    payment_hash: str,
-    wallet: WalletTypeInfo = Depends(require_admin_key),
-) -> Ticket:
-    ticket = await get_ticket(payment_hash)
-    if not ticket:
-        raise HTTPException(
-            status_code=HTTPStatus.NOT_FOUND, detail="Ticket does not exist."
-        )
-    if ticket.wallet != wallet.wallet.id:
-        raise HTTPException(status_code=HTTPStatus.FORBIDDEN, detail="Not your ticket.")
-    if ticket.paid:
-        raise HTTPException(
-            status_code=HTTPStatus.BAD_REQUEST, detail="Ticket already paid."
-        )
-    if not ticket.extra.onchain:
-        raise HTTPException(
-            status_code=HTTPStatus.BAD_REQUEST,
-            detail="Ticket is not an onchain payment.",
-        )
-    ticket = await set_ticket_paid(ticket)
-    send_ticket_notification_in_background(ticket)
-    for queue in payment_listeners.get(payment_hash, []):
-        queue.put_nowait(ticket)
-    return ticket
-
-
 @tickets_api_router.post("/{ticket_id}/resend-email", response_model=TicketResendResult)
 async def api_ticket_resend_email(
     ticket_id: str,