[AnzouBelilita]

Summary

• Complete the missing source and link dependencies for the standalone AGC visual test.
• Add a --window-only mode to smoke-test SDL/Vulkan window creation and pixel presentation independently of AGC GPU drawing.
• Add build and usage instructions to the developer documentation.

Validation

• The standalone visual test builds successfully on Windows with MinGW/Ninja.
• The core CTest suite passes 36/36 tests.
• Vulkan initializes and creates a swapchain on an AMD Radeon RX 580.

Known limitation: --verify still fails with GPU readback: triangle center was not rendered. This change does not claim to fix the AGC draw/readback pipeline; the new window-only mode deliberately skips that verification.

No compiled binaries or generated build outputs are included.

[oneandonlydean]

Closing: --window-only draws a CPU triangle and skips the AGC draw the visual test exists for, and --verify still fails. A PR with only the build fixes (the missing sources and shader_recompiler_agc_driver link) can go in on its own.