Expose active graphics context and host EGL resolver

[DelWow]

What changed

• add a normalized GraphicsContextInfo contract
• report the actual GLFW, SDL3, or EGLUT implementation
• expose the created client API, version, profile, and creation API where the backend can query them
• expose each active backend's host EGL procedure resolver
• preserve exact function-pointer types across the resolver boundary
• delegate both capabilities through the fallback window manager

Why

MCPELauncher previously retained only the requested graphics API. That is not authoritative because GLFW can retry an OpenGL ES 3 request as ES 2, and the GLFW/EGLUT fallback can select a different implementation. The client also needs to query the host ANGLE/EGL display separately from launcher-owned fake EGL exports.

This provides upstream-friendly diagnostics while the context is current, without changing rendering behavior.

Validation

• built as part of the client-only arm64 Debug target on macOS
• packaged GLFW/EGL smoke reported the actual OpenGL ES 3.1 context
• the dedicated resolver returned the host EGL identity used by ANGLE
• final client report separately captured fake guest EGL and host EGL identities
• SDL3, EGLUT, GLFW, and fallback implementations were reviewed for lifecycle and ABI consistency