[Feat] (MG_Impl, MG_Backend): GL_ARB_timer_query on both backends

Implements GL timer queries end to end: a frontend query registry
(modeled on the sync module - mutex-guarded objects wrapping opaque
backend handles behind optional function pointers) serving
glGenQueries/glBeginQuery/glEndQuery(GL_TIME_ELAPSED)/glQueryCounter
(GL_TIMESTAMP)/glGetQueryObject*/glGetQueryiv with GL 3.3 error
semantics and a graceful zero-result fallback when a backend cannot
time.

DirectGLES backs spans with GL_EXT_disjoint_timer_query (context-
generation-stamped handles, bounded result waits). DirectVulkan gets a
VkTimerQueryManager: per-frame-in-flight timestamp query pools reset at
command-buffer begin (outside render passes), records harvested by
frame serial before their pool recycles, elapsed = masked tick delta x
timestampPeriod; handles are stamped with a renderer generation that
also now guards fence syncs across renderer recreation. GL_QUERY_
COUNTER_BITS reports 0 unless the live backend can actually time
(dynamic IsTimerQuerySupported hook), and a failed blocking read keeps
the handle alive so the real value stays reachable once the frame
submits.

GL_ARB_timer_query is advertised only when the device supports timing
and MOBILEGL_DISABLE_TIMERQUERY is unset - LWJGL keys Minecraft's F3
'GPU: x%' line off exactly that extension string; verified on device
(Adreno 830) on both backends.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

MobileGL/MG_Test/CMakeLists.txt

@@ -71,6 +71,7 @@ add_subdirectory(Framebuffer)
 add_subdirectory(Texture)
 add_subdirectory(VertexArray)
 add_subdirectory(Program)
+add_subdirectory(Query)
 if (ENABLE_INTEGRATION_TESTS)
     add_subdirectory(Backend/DirectVulkan)
 endif()