navidrome+go-zero: pin prune_extensions=[.go] (phase-1 language scope)

Residue prune phase 1 deletes only Go source; navidrome's ui/src
TypeScript front-end is never pruned (evaluator review F3).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NhK2BVApsdR7gAKhE3VrNW

navidrome_navidrome_v0.57.0_v0.58.0/metadata.json

@@ -245,5 +245,8 @@
   "residue_prune": true,
   "prune_keep_list": [
     "core/mock_library_service.go"
+  ],
+  "prune_extensions": [
+    ".go"
   ]
 }

zeromicro_go-zero_v1.6.0_v1.9.3/metadata.json

@@ -402,5 +402,8 @@
   "residue_prune": true,
   "prune_keep_list": [
     "core/stores/dbtest/sql.go"
+  ],
+  "prune_extensions": [
+    ".go"
   ]
 }