feat(vst): S18 VST3 channel isolation — beta ReaSampler 9000 pairs with beta extension only

Fork the VST3 class UID (beta UID minted+frozen), on-disk name, and display
name by the one channel bit via app_version; couple UID selection to the
channel at compile time so a refactor can't split identity from data.

src/vst/reasampler_embed.cpp

@@ -7,6 +7,7 @@
 #include <string>
 #include <vector>
 
+#include "app_version.h"      // vstPluginName (channel-derived embed label, S18)
 #include "editor_geometry.h"  // Rect (shared with embed_strip)
 #include "embed_strip.h"      // the pure strip layout + hit-test
 #include "ext_keys.h"         // kProjExtBanksKey
@@ -161,8 +162,8 @@ bool ReaSamplerEmbed::paint(TPtrInt bitmap, TPtrInt drawInfo) {
         SetTextColor(dc, kRgbText);
         RECT gr{layout.keymap.left + 4, layout.keymap.top, layout.keymap.right,
                 layout.keymap.bottom};
-        const std::string label =
-            samples_.empty() ? "ReaSampler 9000 (bank empty)" : "ReaSampler 9000 (no zones)";
+        const std::string label = reasampler::vstPluginName() +  // channel-derived (S18)
+            (samples_.empty() ? " (bank empty)" : " (no zones)");
         DrawTextA(dc, label.c_str(), -1, &gr,
                   DT_LEFT | DT_VCENTER | DT_SINGLELINE | DT_NOPREFIX);
     } else {