feat(lnd): build LND 0.21.2-beta in-house and sweep the pin

Upstream publishes no docker images; our v0.18.4 image was built in-house.
This pass: official v0.21.2-beta release binaries (sha256-verified against
the signed release manifest), static, on alpine with the same entrypoint
shape as our existing image, pushed to our registry and smoke-run.
LND 0.21 auto-migrates the channel DB on first start (keeping a backup) —
the Update button is user-initiated, never auto-applied.

neode-ui/public/catalog.json

@@ -338,13 +338,13 @@
     {
       "id": "lnd",
       "title": "LND",
-      "version": "0.18.4",
+      "version": "0.21.2",
       "description": "Lightning Network implementation by Lightning Labs. Enables instant, low-cost Bitcoin payments.",
       "icon": "/assets/img/app-icons/lnd.png",
       "author": "Lightning Labs",
       "category": "money",
       "tier": "core",
-      "dockerImage": "source.archipelago-foundation.org/lfg2025/lnd:v0.18.4-beta",
+      "dockerImage": "source.archipelago-foundation.org/lfg2025/lnd:v0.21.2-beta",
       "repoUrl": "https://github.com/lightningnetwork/lnd",
       "requires": [
         "bitcoin-knots"