fix contextrestored webgl renderer call

[BryonLewis]

Noticed a frequent issue in BatAI with this specific error:
d.renderWindow(...)._init is not a function

With this stack trace:

    m_contextRenderer.setResetScene(false);
    canvas.get(0).addEventListener('webglcontextlost', function (evt) {
      return evt.preventDefault();
    }, false);
    canvas.get(0).addEventListener('webglcontextrestored', function () {
      return m_viewer.renderWindow()._init();
    }, false);
    if (m_viewer.renderWindow().renderers().length > 0) {
      m_contextRenderer.setLayer(m_viewer.renderWindow().renderers().length);
    }
    m_this.canvas(canvas);

The specific line is here: https://github.com/OpenGeoscience/geojs/blob/master/src/webgl/webglRenderer.js#L96

I'm guessing it can be happening with annotators and BatAI because of the rather large webGL context it can jump between in a SPA (very large images tiled together along with a decent amount of line annotations).

The problem is that it apppears that the m_viewer.renderWindow() doesn't have a function called ._init()
See: https://github.com/OpenGeoscience/geojs/blob/master/src/vgl/renderWindow.js
Specifically, there seems to be a function called _setup and not _init at: https://github.com/OpenGeoscience/geojs/blob/master/src/vgl/renderWindow.js#L131

It looks like items outside of /vgl use _init() frequently but items inside of that folder seem to use _setup more often.

20260423 Update:

• Added dirty context management to the shader programs and renderers
• This will probably redraw the map when context is restored as well
• Added a test for the functionality of losing and restoring the webgl context through the WEBGL_lose_context extension for WebGL: https://developer.mozilla.org/en-US/docs/Web/API/WEBGL_lose_context

[manthey]

Excellent. Thanks for working through this.