Hub stage 1: pure merge functions for stats, top lists and query logs

Sums dashboard counters, aligns chart series by label, merges top lists by name and
query logs by time (page N cut from the merged head of every server), and reports an
unreachable server as a warning.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tsconfig.json

@@ -4,6 +4,7 @@
   "references": [
     { "path": "./tsconfig.app.json" },
     { "path": "./tsconfig.node.json" },
-    { "path": "./update-check/tsconfig.json" }
+    { "path": "./update-check/tsconfig.json" },
+    { "path": "./hub/tsconfig.json" }
   ]
 }