[codex] interactive swarm simulator replay

[michaelkrasa]

What changed

• Added a C++20 simulator build with mission seeding, A* planning, predictive avoidance, telemetry, and replay generation.
• Added a browser-based replay.html output that is regenerated on every run.
• Added CLI validation for size options so negative and malformed values are rejected.
• Updated the README to explain the simulator outputs and how to run smoke and swarm scenarios.

Why

• The original simulator output was too opaque and did not make it clear what the repo demonstrates.
• The CLI parser previously accepted signed input like --drones -1, which could expand into an enormous size_t.

Validation

• ctest --test-dir build --output-on-failure
• Checked invalid CLI cases:
  • ./build/aerostack_sim --drones -1 --quiet
  • ./build/aerostack_sim --missions 12x --quiet
  • ./build/aerostack_sim --drones 2147483648 --quiet

All tests passed, and invalid inputs now exit with an error.

[michaelkrasa]

Follow-up: the CLI size parser now rejects signed or malformed values before conversion, so inputs like --drones -1 and --missions 12x fail fast instead of being interpreted as huge counts.