Contracts: Update Config::Debug (#14789)

* Update Debug trait

* Rename

* tweak

* fmt

* Better namings

* rm unsafe-debug

* rework doc

* nit

* fix comment

* clippy

* update naming

* Rename file

* fmt fixes

* rename

* Move tracing behind umbrella Debugging trait

* fix

* fix comment

* reorder imports

* comment

* update doc

* add missing doc

* add missing doc

* Update Debugging -> Debugger

* Update bin/node/runtime/Cargo.toml

substrate/frame/contracts/src/debug.rs

@@ -0,0 +1,55 @@
+pub use crate::exec::ExportedFunction;
+use crate::{CodeHash, Config, LOG_TARGET};
+use pallet_contracts_primitives::ExecReturnValue;
+
+/// Umbrella trait for all interfaces that serves for debugging.
+pub trait Debugger<T: Config>: Tracing<T> {}
+
+impl<T: Config, V> Debugger<T> for V where V: Tracing<T> {}
+
+/// Defines methods to capture contract calls, enabling external observers to
+/// measure, trace, and react to contract interactions.
+pub trait Tracing<T: Config> {
+	/// The type of [`CallSpan`] that is created by this trait.
+	type CallSpan: CallSpan;
+
+	/// Creates a new call span to encompass the upcoming contract execution.
+	///
+	/// This method should be invoked just before the execution of a contract and
+	/// marks the beginning of a traceable span of execution.
+	///
+	/// # Arguments
+	///
+	/// * `code_hash` - The code hash of the contract being called.
+	/// * `entry_point` - Describes whether the call is the constructor or a regular call.
+	/// * `input_data` - The raw input data of the call.
+	fn new_call_span(
+		code_hash: &CodeHash<T>,
+		entry_point: ExportedFunction,
+		input_data: &[u8],
+	) -> Self::CallSpan;
+}
+
+/// Defines a span of execution for a contract call.
+pub trait CallSpan {
+	/// Called just after the execution of a contract.
+	///
+	/// # Arguments
+	///
+	/// * `output` - The raw output of the call.
+	fn after_call(self, output: &ExecReturnValue);
+}
+
+impl<T: Config> Tracing<T> for () {
+	type CallSpan = ();
+
+	fn new_call_span(code_hash: &CodeHash<T>, entry_point: ExportedFunction, input_data: &[u8]) {
+		log::trace!(target: LOG_TARGET, "call {entry_point:?} hash: {code_hash:?}, input_data: {input_data:?}")
+	}
+}
+
+impl CallSpan for () {
+	fn after_call(self, output: &ExecReturnValue) {
+		log::trace!(target: LOG_TARGET, "call result {output:?}")
+	}
+}