Tools: add wxPython based GUI launcher for SITL

[mahadsultanchaudhary]

Summary

This PR adds an optional GUI wrapper for sim_vehicle.py to simplify SITL setup while preserving existing CLI behavior. The implementation keeps the GUI logic modular, adds a few usability improvements, and aims to reduce common configuration errors for new users.

Relates to: #32802

---

Classification & Testing

• Checked by a human programmer
• Infrastructure change (helper script)
• Non-functional change
• No-binary change
• Tested manually (SITL)

---

Description

• Adds an optional --gui mode for launching SITL through a simple wxPython interface
• Keeps GUI code isolated in sim_gui_helper.py to avoid bloating sim_vehicle.py
• Parses Tools/autotest/locations.txt for searchable start locations
• Persists last-used settings (vehicle, location, aircraft, checkboxes) via wx.Config
• Adds basic UI validation (e.g. disables Map/Console/OSD when --no-mavproxy is selected)
• Implements directory-aware locking:
  • when launched from a vehicle-specific directory (e.g. ArduCopter/), the GUI locks the vehicle type to match context
  • prevents build-path mismatches and binary-not-found errors from conflicting selections
• Preserves normal CLI behavior inside vehicle directories unless --gui is explicitly passed
• Auto-launches GUI outside vehicle directories when no vehicle is specified
• CLI arguments passed with --gui (e.g. -L, -A) pre-fill and sync with GUI state
• Gracefully exits with install guidance if wxPython is unavailable

---

Testing Performed

Tested locally via SITL.

• GUI opens automatically outside vehicle directories
• Inside vehicle directories, --gui is required
• CLI arguments passed with --gui correctly sync with UI state
• Generated arguments successfully launch the expected simulation
• Directory-aware locking prevents invalid vehicle/context mismatches

AI-Assistance Disclosure

This contribution was AI-assisted. The implementation and GUI structure were developed with AI assistance. I have reviewed, tested, and verified the changes and take full responsibility for this PR.