Checkpoint 10: Linux D3D11 Vulkan forwarding
Parent: PHLEGM-v8-Developer-Distribution-Backend-Policy-09-2026-1007-1547-0909.zip

Implemented:
- Linux D3D11 remains a selectable compatibility label, but gfx.lib now structurally resolves that selection through gfx_vulkan.lib.
- gfx_d3d11.lib is native Windows-only and rejects accidental Linux selection.
- gfx_vulkan.lib accepts the Linux D3D11 compatibility selection and exposes requested backend vs actual presenter identities.
- Runtime dependency metadata removes the superseded DXVK Native payload path; Linux OpenGL/Vulkan/D3D11-compat use system runtimes, and Linux D3D11 presentation is Vulkan.
- The unused gfx_d3d11_native.bi and DXVK license payload were removed.
- Compiler-UI.json hides Vulkan on Windows while retaining OpenGL/D3D11; Linux exposes OpenGL, D3D11 compatibility, and Vulkan.
- Existing tree.lib/archive.lib, tree/icons mode, CHR GUI font, PPU/APU Skip controls, and FPS/frame-skip behavior are retained.

Validation in this environment:
- bash syntax PASS for PHLEGM-Linux-Compiler.sh and Native-Linux-Compile.sh.
- Compiler-UI.json and Runtime-Dependencies.json parse PASS.
- Backend selector/runtime dependency structural assertions PASS.
- Active source/runtime metadata contain no libdxvk/PHLEGM_DXVK/gfx_d3d11_native references.
- Changed normal text files retain CRLF; shell scripts retain LF.

Limitation:
- fbc is not installed/exposed in this container, so this checkpoint does not claim a fresh native FreeBASIC compile or link. Historical stage-08 matrix diagnostics remain included as prior evidence only.
