Create Basic Stress Tests for LM and HM

### What

Launch Manager (LM) and Health Monitor (HM) could benefit from a set of basic stress tests. The goal is not to build a comprehensive benchmarking suite, but rather to increase confidence in the robustness and scalability of the system under heavier-than-usual workloads.

**Launch Manager**

As an initial stress test, we could create a scenario that starts 1024 processes (just because 1024 is a nice round number).

Possible setup:

* 512 reporting processes
* 512 native processes
* Minimize the number of unique executables and launch the same executable multiple times through configuration
* Generate the large JSON configuration programmatically to avoid excessive duplication and simplify maintenance

**Bonus**: Measure and record run-target activation time as the number of processes increases (execute this test with different number of processes).

**Health Monitor**

Similarly, we could design a stress tests focused on Health Monitor scalability.

### Acceptance Criteria (DoD)

At least one stress test for LM and one for HM is available in testing/integration folder.

### How

_No response_