Add household seeding & session (task 07)

- scripts/seed.ts: idempotent pnpm db:seed inserts "Home" household if none exists (powered by tsx)
- signIn callback: first member of household gets owner role, subsequent users get member
- src/lib/session.ts: getCurrentSession() returns { user, household, role }, throws if unauthenticated or unmembered
- /settings/household: member list for all roles; rename form gated to owner only (server action also enforces)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/app/settings/household/actions.ts

@@ -0,0 +1,22 @@
+"use server";
+
+import { eq } from "drizzle-orm";
+import { revalidatePath } from "next/cache";
+import { db } from "@/lib/db";
+import { getCurrentSession } from "@/lib/session";
+import { households } from "@/modules/_core/schema";
+
+export async function renameHousehold(formData: FormData) {
+  const { household, role } = await getCurrentSession();
+  if (role !== "owner") throw new Error("Forbidden");
+
+  const name = formData.get("name");
+  if (typeof name !== "string" || !name.trim()) throw new Error("Invalid name");
+
+  await db
+    .update(households)
+    .set({ name: name.trim() })
+    .where(eq(households.id, household.id));
+
+  revalidatePath("/settings/household");
+}

src/app/settings/household/page.tsx

@@ -0,0 +1,61 @@
+import { eq } from "drizzle-orm";
+import { db } from "@/lib/db";
+import { getCurrentSession } from "@/lib/session";
+import { householdMembers, users } from "@/modules/_core/schema";
+import { Button } from "@/components/ui/button";
+import { Input } from "@/components/ui/input";
+import {
+  Card,
+  CardContent,
+  CardHeader,
+  CardTitle,
+} from "@/components/ui/card";
+import { renameHousehold } from "./actions";
+
+export default async function HouseholdSettingsPage() {
+  const { household, role } = await getCurrentSession();
+
+  const members = await db
+    .select({ user: users, role: householdMembers.role })
+    .from(householdMembers)
+    .innerJoin(users, eq(householdMembers.userId, users.id))
+    .where(eq(householdMembers.householdId, household.id));
+
+  return (
+    <div className="container max-w-2xl py-8 space-y-6">
+      <h1 className="text-2xl font-semibold">Household Settings</h1>
+
+      <Card>
+        <CardHeader>
+          <CardTitle>Members</CardTitle>
+        </CardHeader>
+        <CardContent>
+          <ul className="space-y-2">
+            {members.map(({ user, role: memberRole }) => (
+              <li key={user.id} className="flex items-center justify-between">
+                <span>{user.name ?? user.email}</span>
+                <span className="text-sm text-muted-foreground capitalize">
+                  {memberRole}
+                </span>
+              </li>
+            ))}
+          </ul>
+        </CardContent>
+      </Card>
+
+      {role === "owner" && (
+        <Card>
+          <CardHeader>
+            <CardTitle>Rename Household</CardTitle>
+          </CardHeader>
+          <CardContent>
+            <form action={renameHousehold} className="flex gap-2">
+              <Input name="name" defaultValue={household.name} required />
+              <Button type="submit">Save</Button>
+            </form>
+          </CardContent>
+        </Card>
+      )}
+    </div>
+  );
+}

src/lib/auth.ts

@@ -41,8 +41,6 @@ export const { handlers, auth, signIn, signOut } = NextAuth({
   callbacks: {
     async signIn({ user }) {
       if (!user.id) return true;
-      // Attach user to the single household if not already a member.
-      // (Household is seeded by task 07; this is a no-op until then.)
       const existing = await db
         .select()
         .from(householdMembers)
@@ -51,9 +49,15 @@ export const { handlers, auth, signIn, signOut } = NextAuth({
       if (existing.length === 0) {
         const [household] = await db.select().from(households).limit(1);
         if (household) {
+          const [anyMember] = await db
+            .select()
+            .from(householdMembers)
+            .where(eq(householdMembers.householdId, household.id))
+            .limit(1);
+          const role = anyMember ? "member" : "owner";
           await db
             .insert(householdMembers)
-            .values({ householdId: household.id, userId: user.id })
+            .values({ householdId: household.id, userId: user.id, role })
             .onConflictDoNothing();
         }
       }

src/lib/session.ts

@@ -0,0 +1,31 @@
+import { eq } from "drizzle-orm";
+import { auth } from "@/lib/auth";
+import { db } from "@/lib/db";
+import { householdMembers, households, users } from "@/modules/_core/schema";
+
+export interface CurrentSession {
+  user: typeof users.$inferSelect;
+  household: typeof households.$inferSelect;
+  role: "owner" | "member";
+}
+
+export async function getCurrentSession(): Promise<CurrentSession> {
+  const session = await auth();
+  if (!session?.user?.id) throw new Error("Not authenticated");
+
+  const [row] = await db
+    .select({
+      user: users,
+      household: households,
+      role: householdMembers.role,
+    })
+    .from(householdMembers)
+    .innerJoin(users, eq(householdMembers.userId, users.id))
+    .innerJoin(households, eq(householdMembers.householdId, households.id))
+    .where(eq(householdMembers.userId, session.user.id))
+    .limit(1);
+
+  if (!row) throw new Error("No household membership");
+
+  return row;
+}