v1.0-rc3

Give strum-harp voices a modal resonator instead of osc+envelope (#448)

* Give strum-harp voices a modal resonator instead of osc+envelope

Replaces each strum-harp-voice's plucked-saw + percussive-ADSR VCA
chain with a single resonator operator, tuned by freq and pinged by
gate via its own internal mallet exciter — a real plucked-string ring
rather than a synthesized envelope shape. No `active` output is
needed: a stolen voice reuses the same resonator instance, so its
ring continues under a re-trigger instead of cutting off.

* fix resonator gain

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Co-authored-by: Claude <noreply@anthropic.com>