fix(pS-usage): fail-safe prune protection — in-wire owner nonce + sticky union poison, protect-all on zero identified, abort on unreadable record, rsusage_ prefix

CMakeLists.txt

@@ -339,10 +339,12 @@ target_include_directories(assignment_request PUBLIC src)
 
 # ---------------------------------------------------------------------------
 # 2j'') Pure sample_usage library — NO REAPER, NO SWELL, NO VST3. The pS-usage seam:
-#       the per-instance usage record the INSTRUMENT writes ("usage_<guid>" ext-state,
+#       the per-instance usage record the INSTRUMENT writes ("rsusage_<guid>" ext-state,
 #       the one sanctioned VST-side write) and the EXTENSION reads at prune time. Owns
 #       the wire round-trip, the publish plan (copy-collision fail-safe resolution),
-#       and the liveness fold (which records count against the live FX enumeration).
+#       the liveness fold (which records count against the live FX enumeration,
+#       protect-all when zero identified, abort on unreadable), and the FX identity
+#       matcher.
 #       Linked by BOTH artifacts — the mirror of assignment_request, reversed direction.
 # ---------------------------------------------------------------------------
 add_library(sample_usage STATIC src/sample_usage.cpp)