docs: corrige le README (8 samples, régime mixte lissé/verbatim QAG)

Add QAG sample qag_assemblee_2026_06_17 (ground_truth)

Add QAG sample qag_assemblee_2026_06_17 (audio)

Add QAG sample qag_assemblee_2026_06_03 (ground_truth)

Add QAG sample qag_assemblee_2026_06_03 (audio)

Add QAG sample qag_assemblee_2026_05_27 (ground_truth)

Add QAG sample qag_assemblee_2026_05_27 (audio)

Retrait des audios > 10 min + references (8 samples)

Update README.md

Seed corpus officiels (13 samples) + dataset card

initial commit