This commit finalizes the integration of Palladium Lightning with the Palladium Core backend, making it trivial for developers to spin up and test a local regtest network. Key changes: - Created [TESTING_PALLADIUM.md](cci:7://file:///home/davide/lightning-plm/TESTING_PALLADIUM.md:0:0-0:0) with comprehensive regtest instructions. - Linked the new testing guide in the main [README.md](cci:7://file:///home/davide/lightning-plm/README.md:0:0-0:0). - Ignored `/palladium-bin/` in `.gitignore` to allow developers to drop backend binaries locally without accidentally committing them. - Patched `contrib/startup_regtest.sh` to automatically detect and use these local `palladiumd`/`palladium-cli` binaries if present, removing the strict need to manually export environment variables. - Fixed a false-positive timeout error in `startup_regtest.sh` when parsing the absent `clnrest` plugin logs
CCAN imported from http://ccodearchive.net. CCAN version: init-2606-g5f219f03