feat(telemetry): rollups, alerts, scheduler, health checks, admin server fns

- pure rollup accumulators with tests; daily upserts keyed date/metric/dim
- alert checks with db-backed cooldown and push to admin players
- in-process scheduler started from health probes
- health endpoint checks pb + supertokens, stale-while-revalidate, always 200
- sse connection counter moved to emitter
- telemetry feature server fns: events/errors/groups/rollups/alerts/status

src/app/routes/api/health.ts

@@ -1,19 +1,25 @@
 import { createFileRoute } from "@tanstack/react-router";
+import { ensureTelemetryScheduler } from "@/lib/telemetry/scheduler.server";
+import { getHealthSnapshot } from "@/lib/telemetry/health.server";
 
 export const Route = createFileRoute("/api/health")({
   server: {
     handlers: {
-      GET: () => {
+      GET: async () => {
+        ensureTelemetryScheduler();
+        const snapshot = await getHealthSnapshot();
+
+        // Always 200: a PB/SuperTokens outage must not fail the k8s probes;
+        // restarting the app pod cannot fix a dependency.
         return new Response(
           JSON.stringify({
-            status: "ok",
+            status: snapshot.status,
+            checks: snapshot.checks,
             timestamp: new Date().toISOString(),
           }),
           {
             status: 200,
-            headers: {
-              "Content-Type": "application/json",
-            },
+            headers: { "Content-Type": "application/json" },
           }
         );
       },