Model card: note the inherited canary-1b-v2 final-sigma <unk> issue and its fix

Fix final-sigma/OOV <unk> defect: retrained on tokenizer-normalized targets (greek_norm)

Lead with base-vs-this-model comparison; move four-jobs table into What it does

Remove streaming-vs-offline comparison table

Add base canary-1b-v2 vs fine-tuned comparison; fix repo id in usage snippet

Super-squash branch 'main' using huggingface_hub