GlyphRenderer sizes its GL texture array and fragment-shader sampler array to
exactly TextureAtlas.maxAtlasPages at construction, but _createNewPage pushes
past that cap whenever a 4-page same-size merge is impossible (heterogeneous
sizes, e.g. 1024+512+512+512). The next render throws TypeError: Cannot read
properties of undefined (reading 'version') and rendering freezes — the
single-terminal breakage vector for long heavy-CLI sessions (vscode#322756).
The test builds the renderer with maxAtlasPages=4 (same code path as the
production 8/16/32 values), churns distinct glyphs, and asserts no pageerror,
pages.length <= texture capacity, and an intact pinned header. RED today:
4x TypeError from GlyphRenderer.render.
Anthony Kim
8481bfd8dd