One NVENC session, ring and NV12 path now serve H.264 and HEVC (Codec enum,
Profile::HevcMain). HEVC Main 8-bit 4:2:0 SDR BT.709, MP4/MOV hvc1, parameter
sets only in an hvcC built from the SPS the encoder wrote. The H.265 format is
available through a cached NVENC probe; choosing it is the opt-in, declines are
counted errors. ABI asserts regenerated from nvEncodeAPI.h 12.1 (no drift) and
extended for HEVC; tests, docs and roadmap updated.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>