A capped context still runs the game — only textures wider than the cap
render wrong — so don't hard-block. initGL now returns the context for
"limited"; GPURenderer proceeds and exposes the capped renderer/size via
glLimited (surfaced through MapRenderer), and ClientGameRunner shows the
gate as a warning with a "Continue anyway" button instead of aborting
game creation. GLUnavailableError is back to software/unsupported only.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>