fix: --bars now suppresses early EOS until target bar count is reached

Previously the model could emit EOS before reaching n_bars because the
EOS-suppression was only applied via the n_bars break, not the grammar
bias. Fixed by masking EOS to -inf in the logit bias while
bars_completed < n_bars.

Added _EosHungryModel fixture and test_generate_bars_overrides_early_eos
to catch this regression class.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/generate.py

@@ -268,6 +268,8 @@ def generate_period(
             inp = torch.tensor([ids], dtype=torch.long, device=device)
             logits = model(inp)[0, -1]                        # [vocab_size]
             bias = _grammar_bias(last_id, pos_in_bar, positions_per_bar)
+            if n_bars is not None and bars_completed < n_bars:
+                bias[_EOS] = float("-inf")   # don't let the model stop early
             logits = logits + bias.to(device)
             token_id = _sample_top_p(logits, temperature, top_p)
             ids.append(token_id)