fix: track render pass subpass mode to prevent ImGui secondary violation

When parallel recording is active, the scene pass uses
VK_SUBPASS_CONTENTS_SECONDARY_COMMAND_BUFFERS. Post-processing paths
(FSR/FXAA) end the scene pass and begin a new INLINE render pass for
the swapchain output. ImGui rendering must use the correct mode —
secondary buffers for SECONDARY passes, direct calls for INLINE.

Previously the check used a static condition based on enabled features
(!fsr && !fsr2 && !fxaa && parallel), which could mismatch if a
feature was enabled but initialization failed. Replace with
endFrameInlineMode_ flag that tracks the actual current render pass
mode at runtime, eliminating the validation error
VUID-vkCmdDrawIndexed-commandBuffer-recording that caused intermittent
NVIDIA driver crashes.

include/rendering/renderer.hpp

@@ -668,6 +668,7 @@ private:
     VkCommandBuffer secondaryCmds_[NUM_SECONDARIES][MAX_FRAMES] = {};
 
     bool parallelRecordingEnabled_ = false;  // set true after pools/buffers created
+    bool endFrameInlineMode_ = false;       // true when endFrame switched to INLINE render pass
     bool createSecondaryCommandResources();
     void destroySecondaryCommandResources();
     VkCommandBuffer beginSecondary(uint32_t secondaryIndex);