backport: Merge bitcoin/bitcoin#26366, 26654, 27228, 28629#6684

Open

vijaydasmp wants to merge 4 commits intodashpay:developfrom

vijaydasmp:May_2025_02

Commits on May 25, 2025

Merge bitcoin/bitcoin#26366: rpc, test: `addnode` improv + add test coverage for invalid command

achow101
authored and
vijaydasmp
committed

Commits on May 30, 2025

Merge bitcoin/bitcoin#26654: util: Show descriptive error messages when FileCommit fails

fanquake
authored and
vijaydasmp
committed
Merge bitcoin/bitcoin#27228: test: exempt previous release binaries from valgrind

fanquake
authored and
vijaydasmp
committed
(Partial) Merge bitcoin/bitcoin#28629: test: fix usdt undeclared function errors on mantis

fanquake
authored and
vijaydasmp
committed