WIP - feat(o11y): use local crate name as tracing target

[haphungw]

Refactor the WithClientLogging component to dynamically assign the tracing::event! target field to the name of the crate emitting the log (e.g., google-cloud-storage).

To implement log separation per-client, we converted WithClientLogging from a generic struct wrapping a Future into a #[macro_export]. When client_request_signals! holds a pending HTTP future inside a generated client crate, it expands the new macro locally. env!("CARGO_PKG_NAME") locks onto that caller crate's name, injecting it into the tracing target literal at compile time.

Fixes #5150

[coryan]

Consider:

Suggested change

	let inner_future = $inner;
	async move {
	let output = inner_future.await;
	if let Some(snapshot) =
	$crate::observability::RequestRecorder::current().map(|r| r.client_snapshot())
	{
	if let Err(error) = &output {
	async move {
	$inner.await.inspect_err(|error| {
	let Some(snapshot) =
	$crate::observability::RequestRecorder::current().map(|r| r.client_snapshot()) else { return; }
	... ...
	::tracing::event!(
	name: "experimental.client.request.error",
	target: env!("CARGO_PKG_NAME"),
	::tracing::Level::WARN,
	// Use literals because we don't want to re-export the constants.
	"rpc.system.name" = snapshot.rpc_system(),
	... ... ...
	);
	})
	}

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 98.01%. Comparing base (2cc182b) to head (39e0363).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #5197   +/-   ##
=======================================
  Coverage   98.01%   98.01%           
=======================================
  Files         214      214           
  Lines       44110    44110           
=======================================
  Hits        43236    43236           
  Misses        874      874           

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