fix(btcpay): pin 2.4.2 (actively exploited 2FA bypass); teach drift check the release catalog

BTCPay 2.4.2 fixes a critical vulnerability that upstream reports as actively
exploited: a TOTP two-factor bypass via Greenfield Basic authentication
(btcpayserver/btcpayserver#7491).

Checked the 2.3.9 -> 2.4.2 breaking changes against how Archipelago actually
configures BTCPay; both are inert here:
- 2.4.0 removed the LNBank and Lightning Charge backends. Ours is a direct LND
  connection built by container::lnd::ensure_btcpay_lnd_connection_secret.
- 2.4.2 disables Greenfield Basic auth five minutes after account creation.
  Nothing in the daemon or frontend consumes BTCPay's API.

The manifest bump alone does NOT reach nodes: catalog_image_override makes the
signed catalog authoritative whenever the image repo matches, so a node would
be forced back to 2.3.9. The catalog edit is held locally until the signing
ceremony runs, because an unsigned catalog published to main would be accepted
by nodes (absent signatures are allowed) and would quietly drop authenticity.

check-app-catalog-drift.py only understood app-catalog/catalog.json, where
`apps` is a list. releases/app-catalog.json — the SIGNED catalog nodes actually
resolve apps through — keys `apps` by id and wraps each app's full manifest
under manifest.app. So the checker parsed the file that governs nothing and
raised ValueError on the file that governs everything. It now reads both shapes.

Running it against the release catalog shows the repo and the catalog agree on
content: of 34 image differences, all 34 are the registry host alone and every
tag is identical. The remaining version-string drift (v1.18.0 vs 1.18.0,
1.30.0-alpine vs 1.30.0) is cosmetic metadata, not image drift.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

apps/btcpay-server/manifest.yml

@@ -1,11 +1,11 @@
 app:
   id: btcpay-server
   name: BTCPay Server
-  version: 2.3.9
+  version: 2.4.2
   description: Self-hosted Bitcoin payment processor. Accept Bitcoin payments without intermediaries.
 
   container:
-    image: docker.io/btcpayserver/btcpayserver:2.3.9
+    image: docker.io/btcpayserver/btcpayserver:2.4.2
     pull_policy: if-not-present
     network: archy-net
     secret_env: