Merge ps-w10-vst-channel: S18 VST3 channel isolation

CMakeLists.txt

@@ -34,9 +34,13 @@ set(REASAMPLER_CHANNEL "stable" CACHE STRING "Build channel: stable (default) or
 if(REASAMPLER_CHANNEL STREQUAL "beta")
     set(REASAMPLER_CHANNEL_IS_BETA 1)
     set(REASAMPLER_OUTPUT_NAME "reaper_reasampler_beta")
+    # The VST3 instrument's on-disk name forks the same way (S18) — must match
+    # app_version::vstOutputName() so the artifact name and the in-binary self-id agree.
+    set(REASAMPLER_VST_OUTPUT_NAME "reasampler_9000_beta")
 elseif(REASAMPLER_CHANNEL STREQUAL "stable")
     set(REASAMPLER_CHANNEL_IS_BETA 0)
     set(REASAMPLER_OUTPUT_NAME "reaper_reasampler")
+    set(REASAMPLER_VST_OUTPUT_NAME "reasampler_9000")
 else()
     message(FATAL_ERROR
         "REASAMPLER_CHANNEL must be 'stable' or 'beta' (got '${REASAMPLER_CHANNEL}')")
@@ -944,9 +948,12 @@ if(WIN32 AND EXISTS "${VST3_SDK}/public.sdk/source/main/pluginfactory.cpp")
     # WDL_INC gives LICE for the editor. The VST3 SDK headers come from vst3_sdk PUBLIC.
     target_include_directories(reasampler_vst PRIVATE ${SDK_INC} ${WDL_INC})
     # A .vst3 is a DLL with a .vst3 extension and no lib-prefix. OUTPUT_NAME is the on-disk
-    # product name (S-NAME-1, SETTLED 2026-07-26): reasampler_9000.vst3, matching the
-    # "ReaSampler 9000" display strings. The VST3 class UID (reasampler_vst.h) is unchanged
-    # — the compat anchor a saved instance rebinds by (save-rename-reopen is a DAW-verify).
+    # product name, channel-forked (S18): reasampler_9000.vst3 (stable, byte-identical to
+    # pre-S18) / reasampler_9000_beta.vst3 (beta) — driven by REASAMPLER_VST_OUTPUT_NAME set
+    # from the ONE channel decision above, mirroring the extension's REASAMPLER_OUTPUT_NAME
+    # and matching app_version::vstOutputName(). The two channels install side-by-side; the
+    # per-channel VST3 class UID (reasampler_vst.h) keeps a saved instance rebinding to its
+    # own channel (save-rename-reopen is a DAW-verify).
     set_target_properties(reasampler_vst PROPERTIES PREFIX "" SUFFIX ".vst3"
-        OUTPUT_NAME "reasampler_9000")
+        OUTPUT_NAME "${REASAMPLER_VST_OUTPUT_NAME}")
 endif()