feat(confidence-engine): add authenticated investigation persistence

lib/storage/server-investigation-persistence.js

@@ -0,0 +1,66 @@
+import {
+  createServerSupabaseClient,
+  getAuthenticatedUser,
+} from "@/lib/supabase/server.js";
+
+const SCHEMA = "confidence_engine";
+const TABLE = "investigations";
+
+async function getAuthenticatedPersistenceContext() {
+  const user = await getAuthenticatedUser();
+  if (!user) return null;
+  return { user, supabase: createServerSupabaseClient() };
+}
+
+function throwIfDatabaseError(error) {
+  if (error) throw new Error("Investigation persistence request failed");
+}
+
+export async function saveInvestigation(snapshot, id = snapshot?.id) {
+  if (!snapshot || typeof snapshot !== "object" || !id) {
+    throw new Error("Investigation snapshot and id are required");
+  }
+  const context = await getAuthenticatedPersistenceContext();
+  if (!context) return null;
+
+  const { data, error } = await context.supabase
+    .schema(SCHEMA)
+    .from(TABLE)
+    .upsert({ id, user_id: context.user.id, snapshot }, { onConflict: "id" })
+    .select("id, snapshot, created_at, updated_at")
+    .single();
+  throwIfDatabaseError(error);
+  return data?.snapshot ?? null;
+}
+
+export async function loadInvestigation(id) {
+  if (!id) return null;
+  const context = await getAuthenticatedPersistenceContext();
+  if (!context) return null;
+
+  const { data, error } = await context.supabase
+    .schema(SCHEMA)
+    .from(TABLE)
+    .select("snapshot")
+    .eq("id", id)
+    .maybeSingle();
+  throwIfDatabaseError(error);
+  return data?.snapshot ?? null;
+}
+
+export async function listInvestigations() {
+  const context = await getAuthenticatedPersistenceContext();
+  if (!context) return null;
+
+  const { data, error } = await context.supabase
+    .schema(SCHEMA)
+    .from(TABLE)
+    .select("id, created_at, updated_at")
+    .order("updated_at", { ascending: false });
+  throwIfDatabaseError(error);
+  return (data ?? []).map((record) => ({
+    id: record.id,
+    createdAt: record.created_at,
+    updatedAt: record.updated_at,
+  }));
+}