Improve GPU compatibility, RDNA2 kernels and startup diagnostics

- Match render/compute adapters and gate RR models by GPU capabilities
- Add RDNA2 native texture kernels and fix FP16 rounding
- Harden model builds, cache validation and packaging
- Add startup tracing, timeouts, documentation and regression tests

tools/d4r_build.h

@@ -0,0 +1,4 @@
+#pragma once
+#ifndef D4R_RUNTIME_BUILD_ID
+#define D4R_RUNTIME_BUILD_ID "unidentified (built without runtime_build_id.sh)"
+#endif