Add detector visualization, meta detectors, reload/save flows, and shortcuts

[isakhertin]

Summary

This PR adds GUI support for MAL detectors and meta detectors, improves model/scenario persistence, and adds several workflow shortcuts.

What’s New

• Added detector parsing from .mal files.
• Assets whose MAL type contains detector definitions are now marked in the GUI.
• Draw.io exports now include detector markers for assets with detectors.
• Added meta detector support:
  • Meta detectors can be created as their own item type.
  • Meta detector connections can be saved and loaded through model/scenario YAML.
  • Meta detector connection labels are persisted.
  • Meta detector labels can be edited from the connection context menu.
• Added persistence for attacker metadata in model files:
  • position
  • entry points
  • goals
  • policy
• Improved scenario loading:
  • resolves scenario lang_file paths more safely
  • falls back to the current language when needed
  • restores attacker policy data
• Added current-file save/reload workflows:
  • save currently loaded model or scenario
  • reload currently loaded model/scenario
  • reload the MAL project and reopen the active file when possible
• Added drag-to-pan mode with a toolbar button and shortcut.
• Added/updated tests for:
  • detector parsing
  • detector markers
  • meta detector creation/save/load
  • attacker metadata persistence
  • reload/save behavior

New shortcuts

• Ctrl+S: save current file
• Ctrl+R: reload current file
• Ctrl+Shift+R: reload MAL project
• Ctrl+D: toggle drag mode

Notes

Tests were added for the new detector, meta detector, persistence, and reload behavior.
Detector syntax support is related to the thesis detector language work MasterThesis_DetectorsLang