Host regression: sh tests/run_morph_tests.sh

PASS: 2004 numeric parameter sweeps, named continuous controls, live FM6 carriers/pitch envelopes/transpose
PASS: factory B native PCM endpoint oracle
PASS: all real factory patch B endpoints
PASS: FM6 Manual A/B PCM differs in 4094 samples
PASS: FM6 Up and Down changes PCM (4096 samples)
PASS: QUAD Manual A/B PCM differs in 4096 samples
PASS: QUAD Up and Down changes PCM (4096 samples)
PASS: VA Manual A/B PCM differs in 4096 samples
PASS: VA Up and Down changes PCM (4094 samples)
PASS: PHASE Manual A/B PCM differs in 4096 samples
PASS: PHASE Up and Down changes PCM (4088 samples)
PASS: LOFI Manual A/B PCM differs in 4096 samples
PASS: LOFI Up and Down changes PCM (4096 samples)
PASS: VOICE Manual A/B PCM differs in 4096 samples
PASS: VOICE Up and Down changes PCM (4096 samples)
Morph stereo history 8220 bytes in pool; runtime 5984 bytes
PASS: 11 valid discrete transitions, 20 ms stereo history overlap/restart and exact settled endpoints
PASS: Morph 36 actual CPU1/serial PCM + native state comparisons
PASS: Morph 81 source/preset fixtures; real patch pairs, PCM guards, releases, exact zero amount, config restore, packed pair migration, stable endpoints, chord-only trigger, two-page UI, bass rejection; runtime 5984 bytes
PASS: full-width stereo overlap under UBSan, rapid restarts; history 8220 bytes
