feat: pause and resume methods

[franverona]

Related to #43

• Added pause and resume to CUSTOM_EVENTS
• loop() now stores loopDuration and syncs loopToggle (the direction flag) into element state on each tick
• Loadgo.pause() / $el.loadgo('pause'): clears the interval, sets paused: true, fires loadgo:pause with current
  progress — no-op if not looping
• Loadgo.resume() / $el.loadgo('resume'): restarts the interval from the saved loopToggle and current progress,
  fires loadgo:resume — no-op if not paused
• Vanilla version extracts a shared _startLoopInterval helper to avoid code duplication between loop() and resume()

Types

• Added pause() and resume() to LoadgoAPI and jQuery JQuery interface
• Added loadgo:pause and loadgo:resume to LoadgoEventMap (typed as CustomEvent<LoadgoDetail>)