[Feature Request]: Allow a Workflow to Be Defined as the Required Entry Point for a Pipeline

### What would you like to happen?

Some pipelines depend on mandatory preparation, validation, or control steps that must be performed beforehand by a workflow. Currently, even in these cases, the pipeline can be executed directly through the UI, CLI, API, or server, bypassing these required steps and potentially causing inconsistent executions.

The proposal is to allow a pipeline to be configured with a required entry-point workflow.

When this configuration is enabled, Apache Hop should:

Allow the pipeline to run when invoked by the configured workflow.
Prevent direct execution or execution by any unauthorized process.
Clearly indicate which workflow must be used.
Optionally provide a “Run through the configured workflow” action in the UI.

The goal is not to introduce hidden orchestration or automatically execute a sub-pipeline. The workflow will remain responsible for explicit orchestration. This feature will only ensure that pipelines with prerequisites are started through the correct entry point.

The configuration should be optional, preserving the current behavior for pipelines that do not have a required entry-point workflow configured.

Benefits
Prevents mandatory steps from being bypassed.
Establishes a single, predictable entry point.
Reduces errors caused by improper direct execution.
Keeps orchestration explicit and visible within the workflow.
Ensures consistent behavior across the UI, CLI, API, and server.

### Issue Priority

Priority: 3

### Issue Component

Component: Pipelines

Start by tracing the pipeline execution entry points named in the issue: UI, CLI, API, and server, along with existing workflow and pipeline configuration. Determine how each path identifies authorized execution and define tests showing that configured pipelines accept the required workflow while rejecting direct or unauthorized runs.

Written by the indexing model from the issue text.