Align FSR3 SDK detection/docs with legacy and Kits layouts

docs/AMD_FSR2_INTEGRATION.md

@@ -78,7 +78,7 @@ Runtime note:
 - AMD FSR2 Vulkan dispatch path is integrated and used when available.
 - UI displays active backend in settings (`AMD FidelityFX SDK` or `Internal fallback`).
 - Runtime settings include persisted FSR2 jitter tuning.
-- FidelityFX-SDK `v1.1.4` extern is fetched across platforms and validated in Linux CI for Vulkan framegen source presence.
+- FidelityFX-SDK extern is fetched across platforms (default: `Kelsidavis/FidelityFX-SDK` on `main`).
 - Startup safety behavior remains enabled:
   - persisted FSR2 is deferred until `IN_WORLD`
   - startup falls back unless `WOWEE_ALLOW_STARTUP_FSR2=1`
@@ -96,14 +96,13 @@ Runtime note:
 - `build-linux-amd-fsr2` clones AMD's repository and configures with `WOWEE_ENABLE_AMD_FSR2=ON`.
 - All build jobs clone:
   - `GPUOpen-Effects/FidelityFX-FSR2` (`master`)
-  - `GPUOpen-LibrariesAndSDKs/FidelityFX-SDK` (`v1.1.4`)
-- Linux CI additionally checks FidelityFX-SDK Vulkan framegen files:
+  - `Kelsidavis/FidelityFX-SDK` (`main`) by default
+- Linux CI additionally checks FidelityFX-SDK framegen files (legacy `sdk/...` and Kits layouts):
   - `ffx_frameinterpolation_callbacks_glsl.h`
   - `ffx_opticalflow_callbacks_glsl.h`
   - `CMakeShadersFrameinterpolation.txt`
   - `CMakeShadersOpticalflow.txt`
-- All CI platform jobs build:
-  - `wowee_fsr3_framegen_amd_vk_probe`
+- CI builds `wowee_fsr3_framegen_amd_vk_probe` when that target is generated by CMake for the detected SDK layout.
 - Some upstream SDK checkouts do not include generated Vulkan permutation headers.
 - WoWee bootstraps those headers from the vendored snapshot so AMD backend builds remain cross-platform and deterministic.
 - If SDK headers are missing entirely, WoWee still falls back to the internal backend.