Deduplicate parameter set output and improve PicTiming SEI

[tobbee]

Summary

• Parameter sets (SPS/PPS/VPS) are now only printed when they actually change, eliminating duplicate output for both AVC and HEVC streams
• mp2ts-pslister always shows verbose parameter set info (removed the -ps flag)
• AVC PicTiming SEI output now exposes all clock timestamp fields (ct_type, counting_type, n_frames, time, time_offset, etc.)

Solves #18

Test plan

• Golden file tests updated and passing
• Run mp2ts-pslister on a TS file with repeated identical parameter sets and verify no duplicates
• Run mp2ts-nallister with -sei on an AVC stream and verify richer PicTiming output