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/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>
+  );
+}