Fix bugs and add simulation controls

[drusepth]

• Fix Word.compoundWith() to correctly slice from both words instead of
  duplicating from the same word
• Replace Math.random() agent IDs with unique string IDs to prevent collisions
• Add pause/resume and reset buttons for simulation control
• Add speed slider to adjust simulation frame interval (50-1000ms)
• Limit event log to 100 entries to prevent memory leak
• Replace loose equality (==) with strict equality (===) throughout