docs(plan): tick S5 checkboxes; reconcile performance-map persistence wording to component state

PLAN.md

@@ -223,15 +223,15 @@ instrument (performance map) while root notes come from the bank intrinsics (S2)
 editing the keymap does not touch the bank.
 **Depends on:** S4.
 
-- [ ] Keymap editor in the `IPlugView` LICE editor: assign bank samples to key ranges
+- [x] Keymap editor in the `IPlugView` LICE editor: assign bank samples to key ranges
   (low/high note per sample), each with its own root note (from S2 intrinsics,
   overridable in the performance map).
-- [ ] Tier-1 playback: zoned resolution — a note picks its zone's sample and repitches
+- [x] Tier-1 playback: zoned resolution — a note picks its zone's sample and repitches
   from that sample's root note; one sample per key-region.
-- [ ] Performance-map persistence: the keymap (zones, per-sample assignment) is the
-  instrument's own state — held in the instrument (read/written over the live
-  `"reasampler"` seam per D-B's data-ownership split), never written back as a bank
-  intrinsic.
+- [x] Performance-map persistence: the keymap (zones, per-sample assignment) is the
+  instrument's own state — held in the instrument as VST3 component state (setState/getState)
+  per D-B's data-ownership split; the live `"reasampler"` seam is read-only (bank +
+  intrinsics in, nothing written back), never written back as a bank intrinsic.
 
 ## S6 — embedded TCP/MCP UI (D-D — scheduled in-phase, after the editor)
 **Goal:** Render a compact keymap/level strip **inline in the track/mixer control