fix(gles): keep surface-created EGL context alive past Surface.Destroy

[admin-else]

Summary

On Linux GLES, a Surface that has to create its own EGL context (Wayland, or when the detected window kind does not match the real window) owned that context and freed it in Surface.Destroy. The Adapter, Device, and Queue created from that Surface share the same *AdapterContext and outlive the Surface, so closing the window freed the EGL context first and the later Device.Destroy locked a nil EGL context.

Reproduced signature:

ERROR gles: AdapterContext.Lock: nil egl context
panic: runtime error: invalid memory address or nil pointer dereference
... gles.(*Device).Destroy -> gl.(*Context).DeleteVertexArrays(0x0)

This crashes any app that closes a window under GLES when the context is Surface-owned.

Root cause

Instance.CreateSurface has two paths:

• Path A (X11/headless): the Surface shares the Instance AdapterContext — ownsContext=false, so the Instance (released last) frees it.
• Path B (Wayland / window-kind mismatch): the Surface created a new AdapterContext with ownsContext=true.

AdapterContext.Destroy sets eglCtx=nil and gl=nil. In Path B the Surface then destroyed the context that Device/Queue/Adapter still referenced. On shutdown gogpu destroys the Surface (window close), then the Device, then the Instance, so the Device hit a dead context: Lock() logged nil egl context, returned the nil gl table, and DeleteVertexArrays dereferenced nil.

Fix

CreateSurface now adopts the Path B context on the Instance. The Instance is released after the Device and Surface, so the shared context lives as long as everything that uses it. Path B now returns ownsContext=false; the Instance.ctx field is guarded by a mutex.

This mirrors the Windows/X11 model where the context is owned by the Instance, not the Surface.

Testing

• go test ./core/ ./hal/... — pass
• go test -tags integration ./hal/gles/ — pass, including a new regression test TestSurfaceDoesNotDestroyAdoptedContext that destroys a Surface sharing an adopted context, then the Device, then the Instance (the exact shutdown order that used to panic).
• go build ./... — pass

Related

Follow-up to the GLES Linux AdapterContext work (FEAT-GLES-003, #332).