src/generate.py: autoregressive generation with top-p sampling, grammar
masking (ROOT→QUAL→EXT→BASS; EOS only at bar boundary), key transposition,
and optional chord prefix. Partial bars on context truncation are padded
with HOLDs rather than discarded.
scripts/generate.py: CLI wrapping generate_period — accepts mode, key,
time, subdivision, style, function, prefix, temperature, top-p, seed,
tempo; writes .chord and optional MIDI.
src/tokenizer.py: fix docstring vocab size (81→84); normalize redundant
BASS_<note>==root to no slash in _tokens_to_symbol.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
