feat(telemetry): generic event aggregates and usage range presets

- rollups emit event.count (dim name) and event.detail.count (dim name|detail
  from props.source/emoji/tournament)
- usage screen: events section with tap-through breakdown; 7d/30d/180d/custom
  date-range presets

src/lib/telemetry/rollup-core.ts

@@ -14,6 +14,7 @@ export interface ClientEventRow {
   session_id?: string;
   route_id?: string;
   value?: number;
+  props?: { source?: string; emoji?: string; tournament?: string } | null;
 }
 
 export interface ClientErrorRow {
@@ -64,6 +65,8 @@ export interface ClientEventAccumulator {
   sessions: Set<string>;
   pageViewsByRoute: Map<string, number>;
   vitals: Map<string, number[]>;
+  eventCounts: Map<string, number>;
+  eventDetails: Map<string, number>;
 }
 
 export const newClientEventAccumulator = (): ClientEventAccumulator => ({
@@ -71,8 +74,13 @@ export const newClientEventAccumulator = (): ClientEventAccumulator => ({
   sessions: new Set(),
   pageViewsByRoute: new Map(),
   vitals: new Map(),
+  eventCounts: new Map(),
+  eventDetails: new Map(),
 });
 
+const eventDetail = (row: ClientEventRow): string | undefined =>
+  row.props?.source ?? row.props?.emoji ?? row.props?.tournament;
+
 export const accumulateClientEvents = (acc: ClientEventAccumulator, rows: ClientEventRow[]) => {
   for (const row of rows) {
     if (row.player) acc.players.add(row.player);
@@ -86,6 +94,13 @@ export const accumulateClientEvents = (acc: ClientEventAccumulator, rows: Client
       const values = acc.vitals.get(metric) ?? [];
       values.push(row.value);
       acc.vitals.set(metric, values);
+    } else {
+      acc.eventCounts.set(row.name, (acc.eventCounts.get(row.name) ?? 0) + 1);
+      const detail = eventDetail(row);
+      if (detail) {
+        const key = `${row.name}|${detail}`;
+        acc.eventDetails.set(key, (acc.eventDetails.get(key) ?? 0) + 1);
+      }
     }
   }
 };
@@ -157,6 +172,13 @@ export const buildDayRollups = (
   push("page_view.count", "", totalPageViews);
   push("page_view.sessions", "", clientEvents.sessions.size);
 
+  for (const [name, count] of clientEvents.eventCounts) {
+    push("event.count", name, count);
+  }
+  for (const [key, count] of clientEvents.eventDetails) {
+    push("event.detail.count", key, count);
+  }
+
   push("client_error.count", "", clientErrors.total);
   for (const [group, count] of clientErrors.byGroup) {
     push("client_error.count", group, count);