diag(track-a): test contained Xvfb modulepath for GLX

[blakinio]

Track A RUNTIME-INFRA — contained Xvfb modulepath GLX discriminator

Task: OTC-20260816-track-a-xvfb-modulepath-glx-probe.
Base: exact trusted main@d3f186414256151c9d5e03f34c5a9026b1fba500.
Execution: exactly one governance-compliant ephemeral_isolated Xvfb-only support-process workflow on synology-otclient-01.

Input: Draft #416 proved the exact contained Xvfb and contained libglx.so/libglamoregl.so capability surface. Draft #417 then proved that +extension GLX alone leaves GLX absent. The accepted Xvfb launch path has not bound the server to /work/_otclient_tibia_re_state/toolroot/usr/lib/xorg/modules.

This task starts exactly one task-owned contained Xvfb with the same support environment plus only -modulepath /work/_otclient_tibia_re_state/toolroot/usr/lib/xorg/modules and +extension GLX, captures the core-X11 extension list and bounded module/GLX stderr, then cleans up.

No official client/package, VNC, WARP, canonical lease/registration/session, credentials, login, gameplay, Track B or historical #303 surface is accessed. Exactly one valid semantic physical run is allowed.

Research output remains Draft-only; coordinator promotion is separate.

[blakinio]

Coordinator disposition: CLOSED_SUPERSEDED / negative modulepath result retained. This Draft was an intermediate attempt to bind an Xorg module path. The research chain continued to the provider-path discriminator and #421 directly proved the minimal causal fix, now promoted by #427. Preserve this closed PR as negative evidence; do not merge stale task state.