CLN deprecated and then removed the implicit-bech32 default for the
newaddr command. Modern CLN (tested on v26.04.1) responds to
newaddr with only {"p2tr": "..."} and prints the warning
jsonrpc: Note: disallowing deprecated newaddr.addresstype.defaultbech32
This hit our existing code at line 38, which extracted res["bech32"]
unconditionally. Jsmn::Object::operator[] returns an Object with
null pimpl when the key is missing, and the std::string conversion
operator then throws TypeError. The exception propagates up the
Ev::Io chain and is swallowed silently, so Msg::ResponseNewaddr is
never raised.
Downstream symptom: SwapManager hangs forever in state 0
(NeedsOnchainAddress) after restart. Its getting_address flag was
set true when it raised the request, and only clears when the
queue empties via the response chain that never completes. Every
subsequent Timer10Minutes tick short-circuits on the still-true
flag and does nothing.
Fix matches the draft on origin/boltzapi-v2-taproot-reverse-swaps
commit c3dd1de: explicitly request newaddr p2tr and read res["p2tr"].
This is a breaking change for CLN v23.05 and older, but those are
two-plus years out of support already.
