feat: extend community-pulse with full dashboard data + server-side cache

community-pulse now returns top skills, crash clusters, version distribution,
and weekly active count in a single aggregated response. Results are cached
in the community_pulse_cache table (1-hour TTL) to prevent DoS via repeated
expensive queries.

supabase/functions/community-pulse/index.ts

@@ -1,9 +1,12 @@
 // gstack community-pulse edge function
-// Returns weekly active installation count for preamble display.
-// Cached for 1 hour via Cache-Control header.
+// Returns aggregated community stats for the dashboard:
+// weekly active count, top skills, crash clusters, version distribution.
+// Uses server-side cache (community_pulse_cache table) to prevent DoS.
 
 import { createClient } from "https://esm.sh/@supabase/supabase-js@2";
 
+const CACHE_MAX_AGE_MS = 60 * 60 * 1000; // 1 hour
+
 Deno.serve(async () => {
   const supabase = createClient(
     Deno.env.get("SUPABASE_URL") ?? "",
@@ -11,17 +14,37 @@ Deno.serve(async () => {
   );
 
   try {
-    // Count unique update checks in the last 7 days (install base proxy)
+    // Check cache first
+    const { data: cached } = await supabase
+      .from("community_pulse_cache")
+      .select("data, refreshed_at")
+      .eq("id", 1)
+      .single();
+
+    if (cached?.refreshed_at) {
+      const age = Date.now() - new Date(cached.refreshed_at).getTime();
+      if (age < CACHE_MAX_AGE_MS) {
+        return new Response(JSON.stringify(cached.data), {
+          status: 200,
+          headers: {
+            "Content-Type": "application/json",
+            "Cache-Control": "public, max-age=3600",
+          },
+        });
+      }
+    }
+
+    // Cache is stale or missing — recompute
     const weekAgo = new Date(Date.now() - 7 * 24 * 60 * 60 * 1000).toISOString();
     const twoWeeksAgo = new Date(Date.now() - 14 * 24 * 60 * 60 * 1000).toISOString();
 
-    // This week's active
+    // Weekly active (update checks this week)
     const { count: thisWeek } = await supabase
       .from("update_checks")
       .select("*", { count: "exact", head: true })
       .gte("checked_at", weekAgo);
 
-    // Last week's active (for change %)
+    // Last week (for change %)
     const { count: lastWeek } = await supabase
       .from("update_checks")
       .select("*", { count: "exact", head: true })
@@ -34,22 +57,80 @@ Deno.serve(async () => {
       ? Math.round(((current - previous) / previous) * 100)
       : 0;
 
-    return new Response(
-      JSON.stringify({
-        weekly_active: current,
-        change_pct: changePct,
-      }),
-      {
-        status: 200,
-        headers: {
-          "Content-Type": "application/json",
-          "Cache-Control": "public, max-age=3600", // 1 hour cache
-        },
+    // Top skills (last 7 days)
+    const { data: skillRows } = await supabase
+      .from("telemetry_events")
+      .select("skill")
+      .eq("event_type", "skill_run")
+      .gte("event_timestamp", weekAgo)
+      .not("skill", "is", null)
+      .limit(1000);
+
+    const skillCounts: Record<string, number> = {};
+    for (const row of skillRows ?? []) {
+      if (row.skill) {
+        skillCounts[row.skill] = (skillCounts[row.skill] ?? 0) + 1;
       }
-    );
+    }
+    const topSkills = Object.entries(skillCounts)
+      .sort(([, a], [, b]) => b - a)
+      .slice(0, 10)
+      .map(([skill, count]) => ({ skill, count }));
+
+    // Crash clusters (top 5)
+    const { data: crashes } = await supabase
+      .from("crash_clusters")
+      .select("error_class, gstack_version, total_occurrences, identified_users")
+      .limit(5);
+
+    // Version distribution (last 7 days)
+    const versionCounts: Record<string, number> = {};
+    for (const row of skillRows ?? []) {
+      // skillRows doesn't have version — query separately
+    }
+    const { data: versionRows } = await supabase
+      .from("telemetry_events")
+      .select("gstack_version")
+      .gte("event_timestamp", weekAgo)
+      .limit(1000);
+
+    for (const row of versionRows ?? []) {
+      if (row.gstack_version) {
+        versionCounts[row.gstack_version] = (versionCounts[row.gstack_version] ?? 0) + 1;
+      }
+    }
+    const topVersions = Object.entries(versionCounts)
+      .sort(([, a], [, b]) => b - a)
+      .slice(0, 5)
+      .map(([version, count]) => ({ version, count }));
+
+    const result = {
+      weekly_active: current,
+      change_pct: changePct,
+      top_skills: topSkills,
+      crashes: crashes ?? [],
+      versions: topVersions,
+    };
+
+    // Upsert cache
+    await supabase
+      .from("community_pulse_cache")
+      .upsert({
+        id: 1,
+        data: result,
+        refreshed_at: new Date().toISOString(),
+      });
+
+    return new Response(JSON.stringify(result), {
+      status: 200,
+      headers: {
+        "Content-Type": "application/json",
+        "Cache-Control": "public, max-age=3600",
+      },
+    });
   } catch {
     return new Response(
-      JSON.stringify({ weekly_active: 0, change_pct: 0 }),
+      JSON.stringify({ weekly_active: 0, change_pct: 0, top_skills: [], crashes: [], versions: [] }),
       {
         status: 200,
         headers: { "Content-Type": "application/json" },