docs: drop CLI from non-worker-mode description

In CLI mode the bg-worker functions are no longer exposed, so listing
CLI as a "non-worker mode" case is misleading. Non-worker mode now
means classic request-per-process (HTTP requests where no worker is
configured), which is the only case where require still runs with
tolerant lazy-start semantics.

Author: nicolas-grekas

background_worker.go

@@ -276,7 +276,7 @@ const (
 	// requireModeRuntime: HTTP worker inside frankenphp_handle_request.
 	// Assert-only: worker must already be running; never lazy-starts.
 	requireModeRuntime
-	// requireModeNonWorker: non-worker context (classic request, CLI).
+	// requireModeNonWorker: non-worker context (classic request-per-process).
 	// Lazy-starts and tolerates transient boot failures via backoff.
 	requireModeNonWorker
 )

docs/background-workers.md

@@ -48,7 +48,7 @@ Declares a dependency on a background worker. Behavior depends on the caller con
 
 - **In an HTTP worker script, before `frankenphp_handle_request()` (bootstrap)**: lazy-starts the worker (at-most-once) if not already running, blocks until it has called `set_vars()` at least once. Fails fast on boot failure (no exponential-backoff tolerance): if the worker's first boot attempts fail, the exception is thrown right away with the captured details. Use this to declare dependencies up front.
 - **In an HTTP worker script, inside `frankenphp_handle_request()` (runtime)**: assert-only. The worker must already be running (declared with `num 1` in Caddyfile or previously required during bootstrap). Never lazy-starts. Throws immediately if the name isn't known. Use this to assert a dependency without starting anything.
-- **In non-worker mode (classic request, CLI)**: lazy-starts the worker and waits up to `$timeout`, tolerating transient boot failures via exponential backoff. Same behavior every request.
+- **In non-worker mode (classic request-per-process)**: lazy-starts the worker and waits up to `$timeout`, tolerating transient boot failures via exponential backoff. Same behavior every request.
 
 ```php
 // HTTP worker (bootstrap)