Feat(Runtime): Implement Debug Hooks and Breakpoint Support

[ztripez]

Summary

Extend the simulation runtime to support interactive debugging hooks. This is a prerequisite for full DAP support.

Tasks

• Add breakpoint storage to Runtime (Signals, Levels, Phases)
• Implement execute_to_breakpoint() or similar fine-grained execution control
• Add hooks to PhaseExecutor to check for breakpoints during:
  • Signal resolution
  • Level completion
  • Phase transitions
• Support "halt" state in Runtime that can be resumed
• Update ExecutionResult to distinguish between full tick completion and debug halts

Related

Epic #242