feat: add Supabase schema, edge functions, and SQL views

Telemetry backend infrastructure: telemetry_events table with RLS
(insert-only), installations table for retention tracking,
update_checks for install pings. Edge functions for update-check
(version + ping), telemetry-ingest (batch insert), and
community-pulse (weekly active count). SQL views for crash
clustering and skill co-occurrence sequences.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

supabase/functions/community-pulse/index.ts

@@ -0,0 +1,59 @@
+// gstack community-pulse edge function
+// Returns weekly active installation count for preamble display.
+// Cached for 1 hour via Cache-Control header.
+
+import { createClient } from "https://esm.sh/@supabase/supabase-js@2";
+
+Deno.serve(async () => {
+  const supabase = createClient(
+    Deno.env.get("SUPABASE_URL") ?? "",
+    Deno.env.get("SUPABASE_SERVICE_ROLE_KEY") ?? ""
+  );
+
+  try {
+    // Count unique update checks in the last 7 days (install base proxy)
+    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
+    const { count: thisWeek } = await supabase
+      .from("update_checks")
+      .select("*", { count: "exact", head: true })
+      .gte("checked_at", weekAgo);
+
+    // Last week's active (for change %)
+    const { count: lastWeek } = await supabase
+      .from("update_checks")
+      .select("*", { count: "exact", head: true })
+      .gte("checked_at", twoWeeksAgo)
+      .lt("checked_at", weekAgo);
+
+    const current = thisWeek ?? 0;
+    const previous = lastWeek ?? 0;
+    const changePct = previous > 0
+      ? 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
+        },
+      }
+    );
+  } catch {
+    return new Response(
+      JSON.stringify({ weekly_active: 0, change_pct: 0 }),
+      {
+        status: 200,
+        headers: { "Content-Type": "application/json" },
+      }
+    );
+  }
+});