New advanced.block-broadcast-fallback union:
* enabled (default: false)
* grace-seconds (default: 30, range 10-600)
* backup-rpcs: list of full bitcoind RPC URLs, with inline
credentials supported (https://user:pass@host:port/). Up to 10.
docker_entrypoint reads the list with yq, joins with newlines, and
exports BACKUP_RPC_URLS plus PENDING_BLOCKS_DIR=<logdir>/pending-blocks
and PENDING_BLOCKS_GRACE so kamado-api's blocksubmit watcher activates.
If the user enables the fallback but provides no URLs, we log a
warning and disable rather than spam pending-block warnings.
The companion ckpool patch (KamadoPool repo, 0004-dump-pending-block-
for-fallback) writes raw block hex to PENDING_BLOCKS_DIR before each
submit attempt and unlinks on success. The watcher only fires if
ckpool's primary submit fails AND the operator configured backup RPCs.
satoshi
1b67479a4d