regtest: rename castle → libra in default-installed extensions

The castle LNbits extension was renamed to libra. Updates the
default-install / default-user env vars in docker-compose.dev.yml
and the fava-url pin in lnbits-entrypoint.sh (DB filename, slug,
log prefix, comments). The entrypoint script was previously
untracked — tracking it now so the rename persists for fresh
checkouts.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

lnbits-entrypoint.sh

@@ -0,0 +1,40 @@
+#!/bin/sh
+# Wraps the lnbits CMD to keep libra's fava_url pinned at the docker-network
+# address `http://fava:5000`. Libra persists the URL in
+# /app/data/ext_libra.sqlite3 (extension_settings.fava_url) and the model
+# default is "http://localhost:3333", which doesn't resolve from inside the
+# lnbits container.
+#
+# Background loop polls until the table exists, then UPSERTs the row, then
+# exits. Runs alongside the lnbits process so it lands before libra's async
+# _init_fava() task reads the row on a fresh DB.
+
+set -e
+
+(
+  while true; do
+    if [ -f /app/data/ext_libra.sqlite3 ]; then
+      python3 -c '
+import sqlite3, sys, time
+try:
+    con = sqlite3.connect("/app/data/ext_libra.sqlite3")
+    con.execute(
+        "INSERT INTO extension_settings (id, fava_url, fava_ledger_slug, fava_timeout, updated_at) "
+        "VALUES (?, ?, ?, ?, ?) "
+        "ON CONFLICT(id) DO UPDATE SET fava_url=excluded.fava_url, updated_at=excluded.updated_at",
+        ("admin", "http://fava:5000", "libra-ledger", 10.0, time.time()),
+    )
+    con.commit()
+    print("[libra-fava-url-init] fava_url=http://fava:5000", flush=True)
+except sqlite3.OperationalError:
+    sys.exit(1)
+' && break
+    fi
+    sleep 0.5
+  done
+) &
+
+exec uv --offline run lnbits \
+  --port "${LNBITS_PORT:-5001}" \
+  --host "${LNBITS_HOST:-0.0.0.0}" \
+  --forwarded-allow-ips='*'