persist: materialized views — stay current on write, O(1) read + 11 tests

view.sx: persist/view bundles stream + fold + snapshot name; view-attach
subscribes it to a hub so each publish refreshes the snapshot incrementally,
making view-peek an O(1) current read. view-value always folds the tail so it
is never stale. The consumer read-model abstraction (feed indices, audit
rollups, search counters). 122/122.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

lib/persist/scoreboard.json

@@ -10,9 +10,10 @@
     "compaction": {"pass": 11, "fail": 0},
     "durable": {"pass": 15, "fail": 0},
     "blob": {"pass": 14, "fail": 0},
+    "view": {"pass": 11, "fail": 0},
     "recovery": {"pass": 6, "fail": 0}
   },
-  "total_pass": 111,
+  "total_pass": 122,
   "total_fail": 0,
-  "total": 111
+  "total": 122
 }