feat(site): tighten proof, contact, and inquiry delivery

Lead with Batch on the home page, drop the product changelog, add a
domain note, and stop reporting success when SMTP fails.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/lib/contact/deliver.test.ts

@@ -0,0 +1,53 @@
+import assert from "node:assert/strict";
+import { describe, it } from "node:test";
+import { deliverInquiry } from "./deliver.ts";
+import type { Inquiry } from "./schema.ts";
+
+const inquiry: Inquiry = {
+  name: "Anna Müller",
+  email: "anna@example.com",
+  message: "Wir brauchen eine belastbare Abbildung unseres Satzprozesses.",
+  locale: "de",
+  topic: "process",
+};
+
+describe("deliverInquiry", () => {
+  it("saves and succeeds when mail is sent", async () => {
+    const saved: Inquiry[] = [];
+    const result = await deliverInquiry(inquiry, {
+      save: (item) => {
+        saved.push(item);
+        return "id-1";
+      },
+      send: async () => true,
+    });
+
+    assert.deepEqual(result, { ok: true });
+    assert.equal(saved.length, 1);
+  });
+
+  it("does not report success when mail fails after save", async () => {
+    let saved = false;
+    const result = await deliverInquiry(inquiry, {
+      save: () => {
+        saved = true;
+        return "id-2";
+      },
+      send: async () => false,
+    });
+
+    assert.equal(saved, true);
+    assert.deepEqual(result, { ok: false, code: "delivery" });
+  });
+
+  it("returns error when save throws", async () => {
+    const result = await deliverInquiry(inquiry, {
+      save: () => {
+        throw new Error("disk");
+      },
+      send: async () => true,
+    });
+
+    assert.deepEqual(result, { ok: false, code: "error" });
+  });
+});