Replaces the April wreckage (fifteen 70-byte 'working' MIDIs, archived)
with a proper pipeline:
- lib/midikit.py: stdlib-only SMF format-1 writer + reader/verifier
- lib/songkit.py: composition helpers (bar-grid score DSL with a 4/4
bar linter, OPL arps, driving bass, vibrato, drum patterns)
- tunes/: three original tunes - DOS adventure theme (Dm/132),
N64 ambient (G/72), chiptune racing (Em/152) - all with LOOP_START/
LOOP_END markers for game engines
- tools/build_all.sh + tools/check_wav.py: generate, verify, render
via timidity+FluidR3, fail on clipping/dead air
- tests/smoke_test.py: round-trip verified against mido
All three tunes render clean: no clipping, no dead air, durations
match, chromaticism audited against the chord chart.
