Config Splice

Replaces existing scalar values in JSON and .NET XML configuration files (appsettings.json and web.config) from a Pipeline step, preserving every byte it was not asked to change: comments, indentation, key order, attribute order, quote style, BOM state and line endings all survive. Values may be literals or Jenkins Secret Text credentials. Nothing is ever created: a property path that does not resolve is a missing path, never a new field.