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>

hub/tsconfig.json

@@ -0,0 +1,23 @@
+{
+  "compilerOptions": {
+    "tsBuildInfoFile": "../node_modules/.tmp/tsconfig.hub.tsbuildinfo",
+    "target": "esnext",
+    "lib": ["ESNext"],
+    "types": ["node"],
+    "skipLibCheck": true,
+
+    /* The hub runs under `node --experimental-strip-types`. */
+    "module": "nodenext",
+    "allowImportingTsExtensions": true,
+    "verbatimModuleSyntax": true,
+    "moduleDetection": "force",
+    "noEmit": true,
+    "erasableSyntaxOnly": true,
+
+    "noUnusedLocals": true,
+    "noUnusedParameters": true,
+    "noFallthroughCasesInSwitch": true,
+    "strict": true
+  },
+  "include": ["*.ts"]
+}