Update index to Belief/Trade canonical naming

INDEX.json

@@ -1,13 +1,17 @@
 {
   "canonical_tiers": [
-    "Faith",
+    "Belief",
     "Trade"
   ],
-  "notes": "Faith maps old v1; Trade maps old v2. Legacy paths retained.",
-  "mappings_sample": {
-    "v1/v1_direct/*": "Faith/benchmark_direct/*",
-    "v2/benchmark_directgen/*": "Trade/benchmark_direct/*",
-    "v2/benchmark_profilegen/*": "Trade/benchmark_profile/*",
-    "v2/benchmark_retrievalgen/*": "Trade/benchmark_retrieval/*"
+  "legacy_aliases": [
+    "Faith",
+    "v1",
+    "v2"
+  ],
+  "notes": "Belief replaces Faith as canonical name for belief-level data.",
+  "mappings": {
+    "Faith/*": "Belief/*",
+    "v1/*": "Belief/* (canonical via organized subtrees)",
+    "v2/*": "Trade/* (canonical via organized subtrees)"
   }
 }