Fix annotation layer initialization race condition

[mattdawkins]

Defer annotation layer creation to onMounted with nextTick and requestAnimationFrame to ensure GeoJS viewer is fully initialized before creating layers. This fixes an intermittent bug where annotations would not display on first load but would appear correctly after exiting and re-entering the viewer.

Changes:

• Add layersInitialized ref to track initialization state
• Move layer creation to initializeLayers() called in onMounted
• Use nextTick + requestAnimationFrame to ensure GeoJS render cycle completes before layer creation
• Add guards in updateLayers() and updateAttributes() to prevent calls before initialization
• Move event listener setup to setupEventListeners() called after layer initialization

Addresses: #365

[BryonLewis]

This isn't a fix at all, a ton of rearranging code that doesn't do anything to address the reference issue. Doesn't fix #365 at all because if I remove the second updateLayers call it does the same thing asif I removed the [0,1].forEach(() => updateLayers());

[BryonLewis]

For all this code it doesn't fix a thing. It's still calling a double updateLayers to draw the first version. I pulled and checked this. This is not the solution to the related bug.

[mattdawkins]

You're right, the previous approach was flawed. I've updated the fix to properly address the root cause.

The Problem:
The original code (and my first attempt) used timing heuristics (onMounted → nextTick → requestAnimationFrame) hoping the GeoJS viewer would be ready. But the viewer is created asynchronously in the annotator when the first image loads - there's no guarantee timing-based approaches will work.

The Actual Fix:
Instead of guessing with timing, LayerManager now watches annotator.ready.value:

watch(
  () => annotator.ready.value,
  (ready) => {
    if (ready && !layersInitialized.value) {
      initializeLayers();
      updateLayers(...);
    }
  },
  { immediate: true },
);

This required exposing the existing state.ready property through the MediaController interface. The annotator components already set ready=true only after initializeViewer() completes, so this properly synchronizes layer creation with viewer initialization.

I also removed the double updateLayers() call since, as you pointed out, it was cargo cult code that never actually fixed anything.

[BryonLewis]

This still doesn't fix the issue of first time rendering when loading data and introduces more issues, including issues with the geoJS layer annotation-clicked handler. That state.ready variable is true before the watcher is even run so it never has a chance to be false inside of the LayerManager either.

[mattdawkins]

Damnit claude.

This issue came about when I noticed some annotations still didn't show in the viewer the first time I went into them (but showed in the list). The initial commit seemed to make it go away, but it's a non-deterministic issue so hard to say.